Red Panda Adventures (77) - The Case of the Missing Muse

A seemingly impossible crime, left unfinished just before the moment of triumph. On the floor, a single clue, a sheet of paper left blank and unsigned. Can this be a token that one of the Red Panda's deadliest enemies has returned? And if so, why did the villain shy away from the coup de grace? And who is the sinister face behind the Case of the Missing Muse?