Malachi and the Twilight Zoo — Abigail Hilton

Eve, Malachi, and Athena are enjoying a quiet winter in Gwen's home, full of stories and sleepy afternoons. Then they receive a surprising message. A group of cats are asking for their help. Even more shocking: the cats are lions. In order to provide assistance, Eve and Malachi must take their adopted family into the zoo, where the local rats are unfriendly, a groundskeeper may be insane, and an old enemy is waiting to pounce. If they don't go, a young lion is certain to meet an untimely end in the shadows of the twilight zoo. This is book 5 in the Eve and Malachi Series.