Spring 1884 Kat Holloway's employer abruptly decides the family will spend Easter dinner at a friend's house in Portman Square, where Kat will substitute for that home's cook, who has fallen ill. Kat strongly objects but has no choice but to obey. Intrigue and sudden death in that household, however, catches Kat off-guard and plunges her, Daniel, and their friends into yet another dangerous mystery.