友達の妹が俺にだけウザイ

Akiteru Ooboshi has built a comfortable, low-effort life around not getting attached to anyone, until Iroha Kohinata, his best friend Ozuma's little sister, starts letting herself into his apartment daily. She's sweet and proper to everyone else and relentlessly, deliberately annoying only to him, and Akiteru can't work out if he's being bullied or courted. Other girls start noticing him too, each with her own way of making his carefully ordered life harder to keep ordered.