GENKING

Two children of rival gangster families are betrothed to each other to ensure a truce. They dislike each other in the beginning, but over time they start to like each other.

The story centers on Ayame and Tsubaki, who are researchers at a lab in the biology department of T University. Ayame is a "returnee," someone who lived abroad for a while and then returned to Japan. He does things at his own pace...