"Lucky Bastard" by Deborah Coonts; Forge ($25.99)

Mysteries that feature large swaths of humor must balance the line between the comic and the thoughtful nature of crime fiction.

Deborah Coonts has no trouble brewing a fine mix of wit and seriousness in her highly entertaining "Lucky Bastard," the fourth in her Lucky O'Toole series.

Coonts finds plenty of laughs in the artificial city of Las Vegas, which may have invented the phrase "over-the-top," and in her heroine, who is the acerbic head of customer relations at the gaudy Babylon Hotel, a mega casino-resort on the Vegas strip. But "Lucky Bastard" quickly takes a more somber tone when the plot deals with a young woman's death and the weighty themes of unconditional love, secret lives and past transgressions. And as much as Vegas lends itself to a laugh riot, "Lucky Bastard" also delves into the city's infrastructure where inefficient storm drains can become deadly when jammed with unexpected summer monsoon showers.

Lucky is dealing with the Smack-Down Poker tournament, which has brought an even more than usual swarm of thieves, cheaters, hookers and media to Babylon. But the murder of a young woman found in the casino's onsite Ferrari dealership takes priority, as does another unexpected death. Lucky hopes she can count on Paxton Dave, a private investigator who used to work for Babylon's security force, but his private life proves more troublesome than she could imagine. Instead, Lucky finds a sleuthing partner in Cole Weston, a hearing-impaired professional poker player who a thug of a dealer tried to prevent from playing.

Although she often "drowns ... in a romantic tsunami," Lucky proves to be a resourceful, bright heroine who knows how to maneuver the wild world of Las Vegas while keeping her sanity. That's quite a feat considering her background. She only recently found out that the owner of Babylon also is her father. As for her mother, Mona is the respected owner of Mona's Place, considered "the best whorehouse in Nevada"; Mona also happens to be pregnant.

The energetic "Lucky Bastard," and Coonts' other novels in her series, may be the only sure bet that Las Vegas can offer.