As a conclusion to his serialized work "Resonance," mangaka Chikara Nagai plans to kill off Lin, one of the most important characters, in an unexpected turn of events according to the popular view. Following a session of mostly negative feedback from his editor, Nagai faces yet another sleepless night drawing the last few panels of his manga.


In drowsiness, he discovered a furious Lin escaping after stealing the manga spread where he dies. Before Nagai can process anything, he gets sucked into the world of his own creation and finds himself amid a fight scene between the heroine Satoko Miura and the villain, "The Masque." Unable to distinguish between dream and reality, Nagai works with Satoko to search for an alternate ending to the manga, so he can find an exit and return to the real world.

Opus was Satoshi Kon's last manga before he debuted in the anime industry through Perfect Blue. The manga had been axed due to the cancellation of its publishing magazine. A missing end chapter to Opus was found after Kon's death.