Hirabayashi Takuto lives with his two friends Hano Kyohei and Okayama Hajime at a share house. They have been friends since high school. Takuto Hirabayashi now works at a company, Kyohei Hano works at a trading company and Hajime works for an apparel brand.
One day, Takuto comes home from work and finds a baby sleeping in the room. Kyohei and Hajime also come home. They read a letter on the desk that says “the baby is yours.” Who is the baby’s father? All three are not very responsible and guess that one of the other two guys is the father. At that time, they notice the baby has a fever.