Maisie Hitchins longs to be a detective. She's sure there are lots of adventures to be had on the streets of Victorian London. And, together with her faithful puppy, Eddie, she is determined to follow even the slightest scent of a mystery - no matter what! Maisie receives a peculiar parcel from her father containing papers he tells her he doesn't want to keep on board his ship. Meanwhile, Alice's father is having a run of bad fortune - two of his ships have disappeared and he has lost a lot of money. He travels to China to try to save his business and Alice comes to stay with Maisie at Albion Road. Maisie is sure she can solve the mystery herself, without travelling hundreds of miles, and heads down to London's sprawling docks to investigate. Can she discover what is happening far away at sea, bring her father home and save Alice's fortune?