Devonie Lace has just returned from a glorious honeymoon with her husband Lance. He is eager for their life to begin, uncomplicated by Devonie’s knack for stumbling into mysteries and her determination to solve them. After a quick stop at the hospital where he works, Devonie witnesses a man trying to smother a patient. It turns out that the patient is amnesiac, found by a fisherman in the ocean with no explanation.

Naturally, Devonie wants to help this woman. When the woman’s memory returns, she tells Devonie that her name is Ronnie and she is the sister of a racecar driver. She was supposed to go with him and others to Cabo St. Lucas on vacation but was left behind. Soon, Devonie discovers that she is also an inventor and has discovered a way to make cars run without gasoline. As Devonie digs deeper into Ronnie’s life she becomes the target of the people who tried to kill Ronnie for her inventions and her car designs.