Recently widowed Goro Kawakubo, the dashing son of a famous artist, hires an au pair, Masayo, to care for his eight-year-old daughter, Momoko. Her only companion is her cat, Lala. Masayo quickly falls in love with Goro's lifestyle and then the widower himself. One fateful night, Goro meets the gorgeous Chinatsu, who soon becomes his girlfriend. Masayo is tormented with jealousy but can do nothing but watch.
Meanwhile young Momoko demonstrates more and more macabre tendencies, further retreating into a world only she and her cat occupy. As Chinatsu tries to win over the potential stepdaughter's affection, she reaslizes she has to compete with Lala, and Chinatsu hates cats. The tension among the wome nin Goro's home climaxes with a shocking act of femme fatale vengeance.
Koike's trademark blend of traditional romance and suspense turns the happy-ending formula of love stories on its head with an added jolt of intrigue and mystery.