Christmas is approaching. Airin, Sherlock, and Arsène find themselves in London. And while Sherlock is not in a good mood, as always happens during the holidays, a sudden mystery sweeps the three friends into a terrifying adventure. The director of the British Museum has been murdered under very enigmatic circumstances, and the newspapers speak of a dark curse that has its roots in ancient Egypt. Airin, Sherlock, and Lupin immediately begin their investigation, unraveling the thread of a very strange case whose solution, right up to the last moment, will be unexpected and unpredictable.