The book starts off with Septimus getting his promotion and his fist assignment (to pick up his friends from the port). Once Septimus gets his friends, they meet an old figure from the past and stay with him for the night. On the way back to the Tower, they crash into one of the Isles of Syren. This is where the book takes place. Meanwhile Wolf Boy and Lucy go on an adventure that also takes them out to the Isle. They witness an object being stolen and placed strategically. They meet up with Septimus and Co.
