A catered New Year's Eve : a mystery with recipes

"It's been years since Bernie and Libby's parents became estranged from Ada Sinclair's side of the family--though the reasons for the rift are lost to history. The sisters, however, are intrigued when Ada makes contact. She tells them about the long-ago deaths of her father and his business partner, which happened within hours of each other--and were both ruled accidental. Ada thinks otherwise--and has a plan. On New Year's Eve, she'll gather a g...