From Kirkus:

A funeral reveals a puzzle fueled by decades-old family intrigue.

Maggy Thorsen’s business partner, Sarah Kingston, has always been a prickly soul—but the people she loves, she loves steadfastly. She raised Courtney and Sam Egan after the death of their mother, Patricia, the third partner in the Uncommon Grounds coffee shop. And she served as a surrogate mom to her sister Ruth’s daughter, Arial. Although Ruth didn’t formally abandon Arial, Ruth and Sarah’s mother, Edna Mayes Kingston, never let Ruth forget that Arial was born out of wedlock, the result of a one-night stand. Sarah offered the otherwise unwelcome Arial the love and support the girl’s mother and grandmother denied her. Still, Sarah is shocked when Ruth fails to attend Edna’s funeral. When Maggy and Sarah go back to Edna’s house, they discover why: Ruth never picked up Arial from the airport because she was lying in bed, overcome by carbon monoxide. As Ruth languishes in the hospital with a coma, Sarah, Arial, and Maggy review a host of possibilities. Was Ruth poisoned by accident? Did she try to kill herself? Or did someone try to murder her? The answer brings the trio back to Edna’s childhood home in Monterey, California, a trip that sheds new light on how Sarah became the person she is.

A challenging puzzle with an ingenious twist that’ll keep you awake more effectively than a shot of espresso.

From Booklist:

Maggy Thorsen (last seen in Any Pot in a Storm, 2023), along with her coffeehouse partner, Sarah Kingston, greets visitors at Sarah’s mother’s wake. They particularly notice one young woman, who shares a different story for how she knew the deceased with each person she talks to. Sarah’s sister, Ruth, never shows up to the wake and doesn't pick her daughter, Arial, up
from the airport as planned. When they travel to the Kingston house for refreshments, they find Ruth in a coma, overcome by carbon-monoxide fumes caused by a faulty furnace. At first they think deferred maintenance led to Ruth’s poisoning, but Maggy comes to believe the furnace may have been tampered with. While Ruth remains in a coma, Maggy, Sarah, and Arial delve
deeper into Ruth’s past, traveling to California to uncover the truth about the events that led to Arial’s birth. The Kingston family’s deeply troubled, complicated relationships frame a story chock full of family secrets and plot twists that Maggy manages to unravel.

Share with fans of Laura Childs’ Theodosia Browning tea-shop cozies.