Maine Mystery Books in Order

Richard J. Cass's Maine Mystery line begins with The Last Altruist, a standalone-style crime thriller that shifts his focus from Boston jazz bars to Portland, Maine. The book follows Ardmore Theberge, a former Army investigator whose military career ended after a violent confrontation with a superior officer. Back in Maine, he wants a quieter life and plans to make hand-drawn maps for a living.

That plan does not last. Ardmore becomes close to Rebekah Horvath, who owns a small stationery shop, and to her son Robbie, who has developmental disabilities. Rebekah is under pressure to sell several buildings she owns. When a real-estate developer is murdered inside her shop and evidence points toward Robbie, Ardmore cannot simply walk away.

Then Robbie disappears.

The mystery gives Ardmore a clear, personal goal: protect Robbie and find out who benefits from framing him. The case soon reaches beyond a single killing. Rebekah's past work in the Foreign Service, two powerful politicians, and an old connection from Ardmore's time in Iraq all raise the stakes. What first looks like a local property dispute begins to suggest buried secrets, political leverage, and a threat aimed at more than one person.

Ardmore is not presented as an untouched hero. He carries the consequences of his military past and knows that his own choices have cost him. That history makes him both useful and vulnerable. He understands investigations and danger, but he is also trying to decide what kind of life he can build after service, punishment, and loss. His concern for Robbie and Rebekah gives the story its emotional center.

Portland is an important setting here. The city offers a more compact, close-to-home pressure than the Boston world of the Elder Darrow books. Small businesses, valuable buildings, local influence, and national political connections all share the same streets. The result is a mystery that starts in a familiar place and steadily opens into a broader conspiracy.

The tone is tense and grounded, mixing a murder investigation with a thriller about loyalty, power, and the damage people do to protect their past. Readers who like a troubled but capable lead, a case involving family and community, and a Maine setting with real stakes will find a strong place to begin in The Last Altruist.