1855, London. Rosa befriends Jem, a young bear keeper, and discovers the zoo's animals are in grave danger. When a villainous showman threatens the bears, the children must find the courage to outsmart him and attempt a daring rescue before it's too late...

London, 1855. Twelve-year-old Rosa doesn't want to leave her widowed father and when he reluctantly sends her to live with her wealthy relatives across the river, she feels more alone than ever. She soon discovers the Surrey Zoological Gardens, where she befriends Jem, a young bearkeeper. When Rosa learns the animals are to be sold, and the bears may be killed, she joins forces with Jem, vowing to save them. A travelling menagerie seems like the perfect solution, until Rosa encounters the villainous Mr Murdlock and uncovers the bears' true, dreadful fate. With Jem threatened into silence, and no adult she can trust, Rosa realises the only way to protect the animals is to take matters into her own hands. Together, can Rosa and Jem outwit the dangerous Mr Murdlock and rescue the bears before it's too late?