After an unexpected incident, Ben Miller meets another version of himself: a woman named Bella Miller who shares all his memories and past experiences. From initial flustered hesitation to tacit cooperation, the two face various challenges together involving campus life, shared housing, part-time jobs, friendships and romantic feelings. When Bella joins the University Art Troupe, makes new friends and searches for her own life direction, their relationship evolves from "another self" to partners who understand each other better than anyone else. But why did she appear? The mystery remains waiting to be uncovered.
