In the ocean of Time there is a lost island - wild, inhospitable, and it is impossible to escape from it. Ulysses Moore would never want to return there, but he has no choice, because it is there that the key with which he can find Penelope is located. Ulysses Moore does not yet know that a whole chain of events is already unfolding and, wanting to take revenge on him, he returns from the past, his most dangerous enemy. The moment has come when fantasy travelers will have to withstand a decisive test...