Lin Luo, an online novelist born an orphan, was suddenly knocked on the door by a desperate pair of twin sisters one night after the college entrance examination. The elder sister, Wen Shuyao, was resilient and clear-headed, recording all kindnesses as debts; the younger sister, Wen Youning, suffered from complex post-traumatic stress disorder due to long-term abuse, only daring to communicate with people using a notebook. A letter of entrustment from the late director of the orphanage made the soft-hearted Lin Luo decide to take them in. From then on, the three began a life of mutual redemption in a dilapidated rented room. He took in two worlds, while they only wanted to squeeze into the rest of his single life.