Set in 1980s, in Monga, a Taipei's districts, Mosquito who has grown up without family and friends becomes a member of the gang after a silly fight. For the first time, he finds himself in friendship and brotherhood, since Monk, Dragon and the other members take him under their wing. When a group of mainlanders attempt to take over Monga and threaten the balance among the gangs in the district, friendship is tested, loyalty is questioned and Mosquito realizes that in this world of violence, things may be much different from what they seem to be.