A cat and dog crossed a rainbow bridge, but came back as humans?! Jung Woo lives alone after losing his parents at the age of 20 and working part-time in his Uncle's shop. One day, two strangers enter the house and claim they were Choco and Milk! The two were indeed the reincarnation of Choco and Milk whom he raised from childhood to high school and lost by an accident. The arrival of the two embarks on a new beginning and the quest to discover love.