Seiya Kawasumi is an ordinary boy of a modest household with 4 other members: father, step-mother, and 2 sisters.

However, his humble happiness was broken when his father suddenly got fired and they are left with a large debt. To avoid the separation, Seiya looked for a live-in job for him and his family. But it was hard to find a suitable place and when he was about to lose hope, his classmate Hiruda who was often bullied by others came up to him with an offer. He didn't realize what his true intention was at this point...