Imaizumin-chi wa Douyara Gal no Tamariba ni Natteru Rashii 4

Imaizumin and girls move into a new apartment that is much bigger and cheaper than the old one. Although his new apartment is perfect, an issue arises when his new neighbor turns out to be Risa, Reina’s older sister, who seduces Imaizumin when the girls are not around.