Hoshizora no Memoria

When Kogasaka You was young, he lived in the small town of Hibarigasaki. Due to family circumstances, though, he moved away a month after he made his first friend, a girl with long white hair. Before he left, he and the girl promised that he would come back to see her and when they did they’d get married.

Seven years later, his mother died and he and his little sister Chinami were forced to move back to the town. Unlike when he was a child, however, You has grown to be rather amiable and witty. Rather than having no friends, he makes them quite easily and quickly becomes part of a group that he later learns makes up the school’s astronomy circle, which can’t quite make it to Club Stub level.

However, more important to You than any of that is his promise with the girl. While he genuinely believes that he didn’t love her and thus didn’t take the marriage proposal seriously, she was still his best and first friend. However, when he finally arrives at the promised meeting place, he finds it blocked off. Undeterred, he sneaks in and finds a girl who looks just his childhood friend did seven years back, only she carries a scythe and calls herself Mare.

Hoshizora no Memoria is a Visual Novel released by the company Favorite in February 2009. It received a Fan Translation into English in late March 2012.

Tropes used in Hoshizora no Memoria include:

Adults Are Useless: Averted, most of them play a substantial role, particularly when helping their kids get to the bottom of the urban legend.
Batman Gambit: Mayaka invited a miko from the main shrine to send off her daughter, supposedly, but the truth is more complex. She's perfectly capable of doing it herself, but what she was actually going for was to have someone who was a strong fighter show up and grow attached to bother Hikarigasaki and Kosame herself and thus stay to defend her. It probably would not have worked on anyone but Setsuna, who deep down wished for such attachments and was willing to follow such trivial sounding orders.
Big Damn Heroes: Komomo stopping Kosame's attack on Mare with a barehanded catch of her naginata.
Biker Babe: Mayaka is a retired one, apparently.
Blackmail: You tries to get Isuzu to join the astronomy club by using Chinami as a threat. If she doesn’t join, he won’t stop Chinami from annoying her to death.
Book Dumb: Chinami and Asuho
Breaking the Fourth Wall: Chinami's only appearance in Komomo's route.

Chinami: Isn't that a little mean to someone who hasn't had any screentime lately, Onii-chan?!

Brother-Sister Incest: Chinami is one of the romance options and is unlocked after completing Isuzu's route. She's actually his half sister. At the end of the route, Chinami doesn't seem to realize the relationship is at all strange, but since she was already kind of glompy You is able to keep it hidden from everyone but Shino.
Catch Phrase: Chinami’s cry of ‘Onii-chan! Onii-chan! Onii-chan!’
- Isuzu's "You should just die."
- Ren's "Hopeless mortals... giggle giggle." Turned Up to Eleven in Yume's route, when it's all she says as part of the kaleido-orgel's "melody".
Catch Your Death of Cold
Chick Magnet: You. And it was true at his old school too. And as a kid, though he didn’t know it then.
Childhood Marriage Promise: You remembers the one he made but doesn’t take it entirely seriously. He still intends to meet up with her but oddly enough he can’t find any information on the girl of his memories at all.
Class Rep: Asuho, who is a bit of an airhead but promotes class unity via her friendly attitude. You compares her to the strict, studious tsundere class rep at his old school.
Cosplay Cafe: Asuho works as a maid at one.
- Becomes a bit of a Squick when you realize that the cafe is run by her father.
Covert Pervert: Not really "covert", but Kosame does like to sneak in suggestive dialogue during casual conversation.
- Asuho gets increasingly more perverted and easy to tease after her first time with You.
Dead All Along: Kosame. Doubles as Our Liches Are Different, as her current body was created by Komomo, and borrows the power of the star god in the Seitenguu's meteorite. Her form becomes unstable under the full moon's moonlight, hence she does not show up for the moon-viewing in any of the routes.
Defrosting Ice Queen: Isuzu.
Different As Night and Day: Kosame and Komomo. The former is very friendly and formal with a bit of a malicious streak while the latter is informal, cranky and, if you ask Asuho, a tyrant.
Disappeared Dad: Initially, there's no mention of You's and Chinami's dad. Chinami's dad is dead, and You's dad was avoiding the family due to certain reasons.
DoNotCallMeKomomo: Komomo hates her first name, and gets annoyed whenever anyone, even her mother, calls her by it. This doesn't stop Asuho though, so Komomo eventually drops the issue with her.
First Love: Everyone insists on interpreting the girl from You’s memories as his first love, though he denies it himself.
- Asuho accidentally openly admits to You being hers.
First-Name Basis: Asuho is like this to everyone, even Komomo, and expects You to be the same with her.
The Gadfly: You picks on Chinami mercilessly. Kosame also seems to enjoy teasing and You suspects she joined the astronomy circle specifically to annoy her sister.
Genki Girl: Chinami and Asuho
Generation Xerox: You's situation with Yume and Mare mirrors the Love Triangle with Kasumi/Taiga/Chihiro and Ren.
Head Pet: Kaa-bou tends to hang out on top of Mare’s head.
Heavy Sleeper / Not a Morning Person: Chinami and Shino
Hey, It's That Voice!: A few of them come as a surprise.
- Chinami is Kaoru Mizuhara.
- Mare is Mai Kadowaki.
Hot Mom: Mayaka. You says she doesn’t look much older than he does and she really doesn’t.
- You/Chinami's mother, Kasumi, was quite a looker too.
Ill Girl: Suzuha. Also Yume.
Lethal Chef: Chinami appears to be able to warp space in the kitchen and turns fried eggs into boiled eggs somehow. An attempt at omelets becomes identical in appearance to a well-made salad.
Younger Sibling Fetishization: Chinami, who is the ultra devoted type. Unfortunately, she’s also ultra inept.
Lolicon: You gets called out on this with Mare and Suzuha.
Lovable Sex Maniac: Surprisingly, Kosame.

Komomo: “Everything you say is full with innuendo, huh?”

Mathematician's Answer: When Asuho is asked what the items on a menu mean at the café, she goes into a long indepth answer of their astrological significance and completely skips over what the order actually contains.
Meaningful Name: Mare, who is a shinigami of nightmares, and her last name Ephemeral, meaning short-lived or fleeting (like her initial meetings with You in the prologue, or her very existence).
- Played for laughs during the beach scene, where You compares Chinami to an unexpected wave (her name means "a thousand waves").
Miko: The Hisakaki family and their Seitenguu shrine. Setsuna and Ima are also mikos.
Missing Mom: You/Chinami's mother is dead at the start of the game. Which doesn't stop her from reappearing in some routes as a ghost, making this a bit of a subversion.
Moment Killer: Chinami seems fond of these.
Motor Mouth: Chinami again.
My Name Is Not Durwood: Mare can't get Komomo and Kosame's names right, calling them Mokomoko and Komame instead.
No Sense of Personal Space: Asuho
- Partially justified in that she has bad hearing, and needs to lean in close in order for her to hear.
Oblivious to Love: You.
Parental Abandonment: Asuho's mother is explicitly stated to have left Souichirou for focusing too much on his career and not his family.
Parental Substitute: Shino. Shares a lot of mannerisms with Akiko of Kanon (save for her sleeping patterns, which she shares with Nayuki instead).
Politeness Judo: Attempted by Isuzu at the school gates, but it fails.
Recycled in Space: Almost literally. The plot synopsis bears a startling resemblance to Kanon (right down to the seven year return to the MC's hometown), except with an astronomy motif.
Running Gag: All over the place. Most of them are done surprisingly well, with slight variations each time, and rarely get old.
- Chinami's existence seems to be made up of these. Temple grinding, ripped diaries... The list goes on and on. The prologue alone is full of running gags with her.
- Komomo kicking You or breaking a camera at every occurrence.
- Kosame molesting Komomo in public.
- You's "gentlemanly" acts.
- Okaizumi and the ring puzzle.
- Kaa-kun burning You's head.
Selective Obliviousness: As is pointed out in-story before he admits it, You isn’t as oblivious to Asuho as he pretends.
Shinigami: Mare S. Ephemeral, a shinigami who reaps nightmares.
- There's also an urban legend in the school about a shinigami of love. It turns out to be Ren.
Third Person Person: Chinami.
Through His Stomach: Attempted by Asuho with some success since she’s actually pretty decent at cooking. Attempted with a great deal less success by Chinami.
Too Kinky to Torture: Kosame
Trademark Favorite Food: Chinami loves mayonnaise.
Tsundere: Several, of varying types.
- Right after moving to the new town, You opens up a letter from the girls at his old school and realizes that the class rep was a complete stereotypical tsundere.
- A little bit later Isuzu defines Komomo as one right off the back because she got in her way.
- Shino claims that You is being tsundere towards Chinami. Everyone else begins seeing them in this light as well.
- Mare as well, though she genuinely doesn’t appear to understand why she acts the way she does.
Twincest: Played with. Kosame seems to enjoy molesting Komomo in public, but then she's kind of a troll.
Verbal Tic: Most of the girls have at least one.
- Asuho goes "muu~" whenever she pouts. She also has a tendency to go "erai, erai".
- Mare's "bakabaka" and "damedame." She occasionally uses "pakapaka" instead.
- Yume's tendency to repeat her statements with a "yep, indeed". Example: "Excellent. Yep, excellent indeed."
- Ren voicing her onomatopoeia. Most common example is her "kusu kusu" giggle.
You Gotta Have Blue Hair: Apparently, the only ones with normal hair colors are Asuka, You himself, adult character and the twins, who have a sort of straw blond color. Everyone else has varying shades of impossible hair colors.