Jessica's Mother's Day Present (朱志香の母の日プレゼント Jeshika no Haha no Hi Purezento) is a short story that was originally released as a booklet at the "el Dorado" event on May 2, 2010. It was later adapted into visual novel format with Umineko no Naku Koro ni Tsubasa.
The translation here was made by ameskitty on AnimeSuki, found here.
"We're so lenient!"
"Even though the summoning magic circle was a bit off, we don't mind!"
""After all, the power of love is an important thing!""
"U, uwa...I really did summon you guys. Gramps' grimoire was the real thing..."
Realizing that she had summoned them herself, despite not thinking that she really could do it, Jessica became dumbfounded for a bit.
"Could you make a Mother's Day present?"
"Ah, what a strong love towards your mother I'm feeling. Hey, Zepar! I want to grant this adorable daughter's wish!"
"Same here, Furfur! You know, she's always trying hard for love, isn't she?"
"That's right. After all, she's looking to fulfill forbidden love with a servant. Catching her mother's heart in advance with a mother's day present could be a splendid love strategy!"
"No, no, I wasn't really thinking about it with any deep thoughts like that..."
She had never imagined that these bustling demons would appear.
Jessica was worried about what to get for a mother's day present.
Looking for ideas, she was fishing through the library for a suitable book. Seeing Kinzo's grimoire, finding it amusing, and reading it, she found a method to make a request to a demon.
Because she had summoned the demons while doing so jokingly and half-heartedly, there was no doubt that Kinzo's blood was flowing strongly through Jessica's veins...
"Hey, Zepar. I wonder if there's a magic item appropriate for Mother's Day?"
"We specialize in romantic love! So the love between a parent and child is a bit out of our area of expertise. But after being called out like this, we can't go without giving something, right?"
"I know! We could grant you a fantastic magical item that could remove even the strongest barriers from love with Kanon-kun!"
"Ah, no, I'm sorry, but ordinary things are just fine. I don't want weird magical items..."
"You can't say that! After all, we're two of the 72 highest demons!"
"It'd be impossible for us to say, 'For calling us, your gift is an ordinary carnation!'"
"No, no, just a plain carnation would be good, yeah, plenty..."
The topic had grown pointlessly grand in scale having summoned these troublesome demons, so Jessica placated them with the proposition of "just a plain carnation".
"Well then, if you don't want big magic, then how about a small magic carnation?"
"Ah, now that you say that, we do have a magical carnation like that, don't we? I think it withers after one day, but during that one day, it sends the partner great blessings!"
"Ah...if it's something like that, it'd be fine, I guess. If it's just a day of magic it won't cause a lot of trouble, and there wouldn't be any chance of curses or anything, would there....?
"It's the magic of gratitude. There aren't any curses or negative powers."
"Only that on worrying, you'll forget any of the blessings." 
"But we promise. This magic sends no trouble to the receiver."
"Your mother, who receives the carnation, is given, just for one day, magic protection. That being said, we're demons with the amazing power to satisfactorily grant you this item, so you too should accept it in fear."
I don't really get what kind of effect you have, but please, by the power of magic, bestow protection...
Jessica decided to give the carnation to Natsuhi.
"Mom, here....it's a Mother's Day present."
"Ah, a carnation, is it. ...A somewhat strange carnation, isn't it? Is this by any chance a rare or expensive carnation?"
"N..no, well, not really! It's supposed to be some kind of lucky charm, and it gives you, uh, good fortune if you carry it?"
"Is that so? Thank you. I'll take good care of it."
Zepar and Furfur had said that the next day after giving the present, the effect would present itself from morning until evening.
Jessica wasn't sure what kind of effect the magic would have.
She then turned her thoughts for a bit to the fact that tomorrow was a Monday. A school day.
On returning from school, she'd hear if anything good had happened.
The next day, at the school in Niijima:
"Jessiii! Good morning! ...Is something wrong?"
"Ugghhh...Good morning, Sakukaaa....since this morning my head's been hurting..."
"Oh, nooo, Jessi, a hannngover?! Kyahaha!"
"Ugghhh, your screechy laughter is hurting my head..."
"You say your mother always gets headaches, doesn't she? It could be hereditary. What if you shared your mother's medicine?"
Hm? Jessica suddenly remembered breakfast that morning.
That morning, Natsuhi had a completely bright smile on her face.
"You seem to be in good spirits today, Natsuhi."
"Yes. It must be because the weather has grown so calm. As my headaches seem to have also calmed down, I woke up quite comfortably."
Seeing that exchange between her parents, she thought "Ah, that has to be the effects of the magic carnation."
Oh, so it's like that, is it....
Jessica understood the blessings of the magic carnation.
Surely, the carnation was promised to bring protection to the receiver.
But it hadn't been said whether curses or blessings would be given to the "sender".
...I get it. It's a demon's present, after all. It was simply one of those things that was too good to be true.
The magic of that carnation probably worked by substitution.
It removes the headaches from mom and gives them to me.
In other words, mom is released from headaches today, and, instead, I get them for a day...
At first, she thought it was pretty annoying magic.
But thinking along that line, her feelings changed.
Surely she was having a bad time with the headaches, but thanks to that, for just one day, Natsuhi could spend the day pleasantly.
"...well, I guess you can't have something that's too good to be true. This headache is paying my debt to Mom, so just for today I'll live it out."
Jessica decided that somehow, she'd do her best today.
"What was that!? Gyagyaaa!"
"Hey, what the hell are you talking about?! Gyagyaaa!"
"Je, Jessiii! It's a fight! You gotta stop them, you're the student council president~!"
At school Jessica was a popular student. Whenever there were fights she was often called to stop them.
But today, for some reason, there were numerous fights all around, and each time
Jessica was called over, making her very busy.
Still, Jessica found herself recalling something.
...now that I think about it, Mom told me about that.
When the servants were arguing, she'd watch and arbitrate if it became a fight.
I've probably been burdened with that too, haven't I...?
Today on Rokkenjima, the servants were definitely getting along peacefully without fighting.
Jessica's imagination had been sparked.
At that time, Natsuhi was on Rokkenjima, and, noticing that there wasn't any trouble today, smiling.
"That's why the basketball club is so unfair, right?! Gyagya!!"
"Even if you say that, what about the soccer club!? Gyagya!!"
"So pay the student council fees! Gyagya!!"
"The accounts don't match! Gyagya!!"
"Ehhh! But you said you'd go out with me next week!!"
"Sorry, but work absolutely won't budge on that day..."
Today alone had set a yet-unseen peak in trouble.
Personal troubles, money issues, and even shift problems.
There was absolutely no doubt. All of the usual worries that Natsuhi held had befallen onto Jessica.
As the various issues continued to occur, Jessica unintentionally found herself wondering just what sort of stars her mother had been born under.
But, from shouldering this debt, for just one day, Natsuhi could pass the time in comfort.
That sort of mother's day present wasn't bad, was it...?
Jessica thought so, taking the troubles that should've fallen on her mother, one by one, while enduring a headache, as a challenge.
Rokkenjima main residence. Dinner time
Natsuhi's face was bright and cheerful.
"S, so, Mom. Did something good happen today?"
"Yes. Today was, in all, a good day, almost by fate. It was very peaceful and calm, a lovely day. It must've been because of that good luck carnation you gave me as a present. Thank you very much."
Although today had been a "when it rains it pours" kind of day for Jessica, from her smiling mother's face, she felt that everything had been rewarded.
It would soon be midnight.
The end of Zepar and Furfur's carnation magic.
When midnight arrived, Jessica's headache simultaneously vanished. The carnation magic had expired.
Finally feeling her head cleared, at the same time, Natsuhi was once again afflicted by headaches, and it became a slightly complex feeling.
...it was only for Mother's Day.
That she just for once could carry the burden of Natsuhi's headaches and other torments, it was showing her respect for her mother, wasn't it?
"Hey, Jessica! Although the magic of the carnation is now finished, were you satisfied with it?"
"Natsuhi should've, for just one day, received divine protection."
"Yes, yes! However, I've properly studied the instructions for that magic carnation! You know, the magic of that carnation..."
"I already get it. I, the sender, get all of the misfortune and trouble as a substitute, don't I? Well, things that are too good to be true and all that, the result was that I paid my debt to Mom, so thanks."
Zepar and Furfur exchanged glances, puzzled.
"No, that's not it. That carnation's magic is a 'charm'."
"Spiritual magic cuts through all interference to protect for one day. There shouldn't be any effects that shift the trouble to Jessica-chan, but.."
"No, that's not it, right? Mom's headaches were given to me."
Zepar and Furfur exchanged glances once again.
That the magic the demons had granted gave even the smallest bit of a different effect to a human than stated wounded their pride just a little bit.
"Huumu, somehow we're not agreeing, are we?"
"Yeah, this is a disgrace to demons! Let's properly study the magic of the carnation a little bit more!"
""We hang our names on it - we shall absolutely find out the truth!!""
"No, no, it's fine...Thanks to you, I was able to give a little gift for mother's day. Thank you, really, you have my gratitude..."
""No, that's no good!! We hang our pride on it - we'll absolutely investigate it!""
Zepar and Furfur, replying one-sidedly, erased their forms.
Jessica, giving a sigh of relief and shrugging her shoulders, erased the magic circle.
She probably wouldn't see those two bustling demons again.
...For next year's birthday, she resolved to properly and sincerely choose a gift by herself.
What about that herbal tea Rosa-oba-san had been promoting as a good headache treatment...?
And so, Jessica's mother's day ended...
On the other side, Zepar and Furfur were trying their hardest investigating why the magic that had meant only to protect Natsuhi
had seemed to bring trouble to Jessica.
As a result...they discovered something strange.
"It seems that Ushiromiya Natsuhi, very long ago, made a contract with some demon somewhere."
"That contract, in the one-day magic of the carnation, was set aside."
"Because Natsuhi seems to suffer from headaches, I wonder if she made some sort of exchange request."
"If that's the case, it should be Natsuhi's problem alone, and it should have nothing to do with Jessica."
"...Certainly! If it's like this, let's thoroughly investigate Natsuhi! Just what did she wish for from what kind of spirit?"
Everybody, do you understand?
Why don't we stop for a bit and turn back the pages with Zepar and Furfur?
There was the figure of Natsuhi, embracing the newborn Jessica.
That was the scene where the contract was made.
"Ah, what a darling daughter. She definitely looks just like you, and she'll grow up to be a beautiful girl!"
"Wouldn't that be nice? But because I get headaches, I worry that she will inherit them..."
While cuddling the baby Jessica, Krauss and Natsuhi pleaded.
"Oh, please, God. Please bless our very own daughter that you've finally granted us. I'm sure that she will also suffer from headaches, won't she? No, just like me, from the very core she'll be wrapped in trouble, and the stars of misfortune will take a liking to her. Please grant this child a healthy, beautiful fate. I will take all of Jessica's headaches and misfortune upon myself..."
Perhaps even in Natsuhi's blood, she was communicating with a noble person who transcended humanity.
Natsuhi's wish, before she'd even realized it...seemed to have become a contract with a higher power.
So, from that day forward -
Natsuhi's headaches became the headaches of two people.
- Yeah, ick, I dunno.
- This is also probably wrong, but this is a casual TL anyways.
- what was actually used here was something called "filial piety" (Wikipedia it, it's interesting), but that's a little hard to translate so I used some phrases that most people have probably heard before (even though they sound a bit awkward in context)