A baffling request arrived at the doorstep of the professional hitman Kevin.
"In four days from now, I want you to kill me with a bullet through the heart."

Enticed by a fee of 100 million, Kevin accepted the job—only to find himself hunted by the Ludwig Family, a mafia syndicate with their sights set on the client: a young boy named Luca, whose heart is their target.

Eric, the charismatic center of the popular idol group "Mystic Comet", suffers from a severe heart condition, and only way to save him is with a heart transplant from Luca, his younger twin brother.

"Once the concert is over, my heart is going to be harvested and given to Eric. That’s why I ran away."
"Hey, Kevin, help me get my revenge."

Seeing a reflection of his own past in Luca's plight, Kevin resolves to help the boy carry out his vengeance.

[Translated from Novelgame]