A menagerie-keeper’s daughter, Christine Johnson, makes great friends with Nero, one of her father’s lions. She is able to go into his cage, with him and do as she pleases, the lion even allowing her to tweak his ears. With other people the lion is always surly tempered, but with his mistress he is different and readily performs all the stunts she teaches him. Among the visitors to the menagerie one day, is Basil McDermott. He greatly admires the manner in which Christine handles the animals and obtains an introduction to her after she has left Nero’s cage. Christine is amused when he expresses his fear that Nero will some day hurt her and tells him that they are the best friends in the world. Basil does not like it and tells Johnson so, when, later, he is accepted at the house as Christine’s fiancé. Nero at first takes no notice of Basil, but when he sees that Christine loves him, the ill-tempered beast becomes very jealous and tries to get out of the cage to attack him. When Basil is taken into the cage by Christine, the lion shows his evident hatred of him, but is forced to acknowledge him as his new master. The wedding day soon arrives and everything goes well, until Basil and his wife return to the house with the guests to celebrate the wedding breakfast. Christine leaves the room and enters the menagerie to say good-bye to her old friend, Nero, as her husband is going to take her away. Basil follows later and finds her there. She sends him back to the guests, telling him to let her make her last farewell to Nero alone. Nero senses that she is to leave him and is obsessed by a furious fit of jealousy. When Basil returns a few moments later to fetch his wife, he finds her lying dead beneath Nero’s feet. The lion has claimed her for his bride.