Albert Glittering is a Christmas wood carver. He has spent his whole life creating cozy miniature houses filled with Christmas spirit, just like his father did before him. There is hardly a family in Elvestad that doesn’t have a Glittering house on their windowsill or mantelpiece as Christmas draws near.

The last miniature house old Glittering created has a heart-shaped door. The house is a safe that hides a secret. The door is only meant to be opened when his son Albert finds true love. And now Albert has found Lydia. The only problem is that the house with the heart-shaped door has vanished without a trace. Tiril, Oliver, and Ocho set off on the chase together with Grandpa Franz. Detective Agency No. 2 has got a new mystery on their hands, and you can help them by looking for evidence, solving puzzles, and following the clues.