As spring comes to Scotland and the hills burst into life, a dance is planned for September. The invitations summon home the group of people Violet Aird has cared for most in her long life.
After the success of his first assignment from the UNICORNE agency, fourteen-year-old Michael Malone is given another unexplained mystery to solve. When UNICORNE detect strange goings-on in a comic book shop, Michael is sent to investigate - a task which is made all the more difficult by allies he can no longer trust, and an enemy he can't actually see .