It's almost Christmas in the small English village of Finch, and everyone is sick. Though many of the villagers regretfully decline their invitations to Emma Harris' annual Christmas bash, Lori Shepherd has no intention of missing it. When the winter weather takes a turn for the worse, the guests agree to stay the night. There's general merriment as the Christmas party becomes a pajama party—until a car appears in the winding driveway and promptly slides off the slick pavement and into a ditch. Matilda "Tilly" Trout—a lost and scatterbrained, middle-aged woman—is mercifully unhurt and invited to join. While she catches her breath, Emma asks her other guests if they would like a tour of the Manor, including an odd room which puzzles her. Several guests put forth guesses as to its purpose, but it's Tilly who correctly identifies the room as a chapel. Placing a palm on one of the ornately carved panels, Tilly finds a hidden compartment concealing a pile of treasure—including an exquisitely decorated heart made of solid gold. Where did it come from, and why does it look so different from everything else in the chapel? Why didn't Emma even know about the hidden compartment in her own home until now—and how did Tilly? With Aunt Dimity's otherworldly help and Tilly's bewildering store of knowledge, Lori and friends set out to unravel the mystery behind the heart of gold as, against all odds, Christmas finally comes to Finch.