Set in Newport, Rhode Island, in a world of old money and proud names, Moonlight Becomes You has at its center Maggie Holloway, an independent young woman who has put personal tragedy behind her and become one of the fashion world's most successful photographers. Accompanying her date to a party in Manhattan - a kind of family reunion for the Moore clan of Newport - Maggie is reunited with a woman who had once been her stepmother and who remains one of her fondest childhood memories.

Nuala, now widowed, invites Maggie to visit her in Newport, and when Maggie readily accepts, Nuala plans a dinner for a group of friends so they can meet her long-lost stepdaughter. But when Maggie arrives, she finds Nuala dead, the victim of an apparently random break-in and robbery.

Maggie is heartbroken at the loss and further stunned when she learns that, only days before her death, Nuala had changed her will and left her charming Victorian house to her stepdaughter, the only proviso being that Maggie occasionally visit an old friend, Greta Shipley, who lives in Latham Manor, an elegant retirement home in Newport.

It is when she accompanies Mrs. Shipley to the cemetery to visit Nuala's grave, as well as those of other friends Mrs. Shipley has recently lost, that Maggie discovers that something is wrong. Using her skills as a photographer to aid her in uncovering the secrets hidden on the gravesites, she soon realizes that Nuala's death may not have been a random killing at all but rather part of a diabolical plot conceived by a twisted and unfeeling mind.