Seiran Academy, a prestigious private school. There are three boys known as the "Four Heavenly Kings" of the school. All three say the exact same thing to Guest, who has lost three months of memory in an accident.

"I'm your boyfriend." However, Guest has no memory of having a lover. Furthermore, all three possess different pieces of "evidence."

They all claim to be Guest's partner. Photos, matching rings, messages, shared memories. Everything looks real. But all three are abnormally possessive of Guest. And none of them trust each other. Who is the real boyfriend?

As the story progresses... The photos are edited, the messages are faked, and the rings are counterfeits. The evidence begins to crumble.

Finally, the truth is revealed. In reality, none of them were Guest's boyfriend.

All three had unrequited feelings. Seeing Guest lose their memory after the accident, they thought, "Now is my chance to be with them." Each of them had independently decided to lie.