Please Twins!

おねがい☆ツインズ

The only proof orphan Maiku Kamishiro has of his childhood is a photograph of his old house with himself and a girl he believes is his twin sister. When he moves back into that house, two girls turn up holding the same photograph, Miina Miyafuji and Karen Onodera, and none of the three can say which two are actually related. The light novel follows Maiku, Miina and Karen sharing the house while they try to sort out the truth.