Merlin has been studying computer science on Earth while constructing a secret project called Ghostwheel, a sentient computer based on the Trumps, which Merlin hopes will be able to locate Corwin, who vanished after visiting the Courts of Chaos in the previous novel. Merlin discovers the body of his ex-girlfriend Julia, apparently killed by beasts from another shadow, and subsequently finds himself in sorcerous combat with a lady named Jasra, who has a poisonous sting in her bite. More unnerving is that his best friend Luke apparently knows about both Ghostwheel and Merlin's connection to Amber. He eventually returns to Amber, which is in mourning: the news has just come that Caine has been murdered, and Bleys injured, by a mystery assassin with a rifle – an assassin who demonstrates (with a thrown bomb at Caine's funeral, which misses any other family members) that he has access to something with explosive properties in Amber (which had previously been thought impossible). After the funeral, King Random orders Merlin to shut down Ghostwheel, but the artifact shows it is capable of self-defense, even against its creator, who is saved by the unexpected appearance of Luke – who thus proves, with the ability to traverse Shadow, that he too is no ordinary human. He soon finds that Luke is in fact Rinaldo, son of Brand of Amber, and has been responsible for yearly attempts on his life, on the anniversary of Luke's discovery of Brand's death. Luke imprisons Merlin in a cave of blue crystal which negates his magic abilities and from which he cannot escape.