>>3015158Both of the sisters are in love with the protag. He starts dating Haruka. At the beginning of the game he has an accident on his bike, suffers memory loss. He forgets things that are longer than 13 days ago, his memory basically lasts only 2 weeks.
His mom is busy winning singing competitions overseas or something, so he stays with Chika and Haruka. Chika confesses (because now he's not Harukas boyfriend from the past, the one in the flashbacks), he accepts, drama drama, threesome THE END.
Oh, and he might be related to the sisters (same father) but that's kept ambiguous.
Didn't like the story very much, atmosphere was nice though.