Deck the Halls (first published in 2000) was the mother-daughter duo's first collaborative effort, a brilliant story of high-stakes intrigue and detection played out against a holiday setting. Christmas is only three days away when Regan Reilly, the dynamic young sleuth featured in the novels of Carol Higgins Clark, accidentally meets Alvirah Meehan, Mary Higgins Clark's sharp-witted lottery winner turned amateur sleuth, at a New Jersey dentist's office. When a call comes through on Regan's cell phone notifying her that her father and his driver, Rosita Gonzalez, are being held for $1,000,000 ransom, Alvirah insists that Regan allow her to lend a hand in gaining their release. Complicating the situation is the fact that Regan's mother, the famous mystery writer Nora Regan Reilly, has just been hospitalized with a broken leg, and a brutal winter storm is bearing down on them all. Regan must comfort her mother while trying to meet the harsh demands of her father's kidnappers, who are not just rank amateurs but also laughably inept -- making them all the more dangerous and unpredictable.
In The Christmas Thief (2004), Alvirah and Regan team up again to investigate another kind of kidnapping. When an eighty-foot blue spruce is chosen to spend the holidays as Rockefeller Center's famous Christmas tree, the folks who picked the tree have no idea that attached to one of its branches is a flask chock-full of priceless diamonds that Packy Noonan, a scam artist just released from prison, had hidden there over twelve years ago. When an excited Packy breaks his parole and heads to Stowe, Vermont, to reclaim his loot, he discovers that his special tree will be heading to New York City the next morning, so he and his bumbling crew have to act fast. Meanwhile Alvirah Meehan and Regan Reilly happen to be on a weekend trip to Stowe with their families when they learn that the tree -- and Alvirah's friend Opal, who won the lottery, but lost all her winnings in Packy's scam -- has gone missing.
With two novels filled with twists and turns, intrigue and danger, as well as a hearty dose of good cheer, Mary Higgins Clark and Carol Higgins Clark offer stories that are as breathlessly suspenseful as they are heartwarming -- Christmas classics for many holiday seasons to come.