1934. When Daisy Wells and Hazel Wong set up a secret detective agency at Deepdean School for Girls, they struggle to find a truly exciting mystery to investigate. (Unless you count the case of Lavinia's missing tie. Which they don't.)But then Hazel discovers the body of the Science Mistress, Miss Bell - but when she and Daisy return five minutes later, the body has disappeared. Now the girls have to solve a murder, and prove a murder has happened in the first place before the killer strikes again (and before the police can get there first, naturally),But will they succeed? And can their friendship stand the test?