Popular writer Itsusu Touki learns about the death of his estranged twin brother, Kazuki, and rushes to help in any way he can. This eventually ends up in him being given custody of Kazuki's toddler son, Ryouta. Ryouta quickly comes under the impression that Touki's his father, but this is the least of the young man's problems as he struggles to overcome the trials of suddenly finding himself a single parent.

Ryouta begins to attend the nursery where Kuramoto Yuuji (nickname: Nacchi) is the caretaker. Nacchi's bright and cheerful disposition is an instant hit with kids and parents alike, and Ryouta loves him. But what does Touki think of this sunny guy, his polar opposite in terms of personality?

Kinasuki Shin is a delinquent who always seems to get into trouble; though his martial arts skills usually save him from getting hurt during fights. But his "bad luck magnetism" is always active in full force, and he soon lands in deep debt for causing a car crash.

Takami Ukon is a model and happens to be a student of Kinasuki's school (when he's not busy with photo shoots, at least!) One thing leads to another, and our hapless protagonist soon finds himself commissioned to act as Takami's bodyguard in return for the latter paying off his debts!?

What will become of these two accident-prone guys as they go through high-school life together? Many new characters -- each with weird quirks of his own -- make their appearance as the story progresses. The ensuing drama and hilarity makes Bingo! well worth a read for any BL fan.

Undercover investigator Matsuzawa Tomoya has a blood-stained past and hidden abilities. His new suspect, Kiryuu Yuuki, is one who looks exactly the same as the bloody man who has been in Matsuzawa Tomoya's mind for the past 15 years.