Moses and William reluctantly work together when Eliza becomes a prime suspect, in the latest Miss Scarlet and the Duke:
Eliza may be an excellent detective, but she’s not the most organized person. She has once again lost her mother’s wedding ring. Luckily, it has been found. Unluckily, it was in the city mortuary—which has just experienced a break-in and theft of files. Eliza is arrested.
William is under pressure to charge Eliza, as the chief coroner Thackery wants the case solved as soon as possible, given that three mortuaries were broken into. The new superintendent, Munro, wants to take William off the case, given his friendship with Eliza, but he allows William one day to look into it.
Moses secretly observes William chasing the graverobbers away. William himself has been searching for Moses, and finally finds him outside a bar frequented by graverobbers. William accepts Moses’ offer of help only after immediately being addressed as a policeman when he enters the bar. Moses “hires” the graverobbers William saw; William and several policemen arrest them during the job, in a plan hatched by Moses that earns him payment from William.
William returns to the grave he saw being robbed and is surprised to see flowers there, given that it’s an anonymous grave. He learns from a florist that the grave receives flowers every month—from Thackery. Eliza and Moses have also discovered this, but William forces Eliza to wait outside with Fitzroy when they both arrive at Thackery’s home to question him.
Thackery explains that Mary was his fiancée, long ago. They pulled off a diamond heist together, then he took their haul and fled. She tracked him down and gave him a scar when she learned that he had swallowed the diamonds, but he escaped when she was arrested. He faked his own death using an anonymous corpse, and has sent flowers to that grave ever since. He reinvented himself and started a new life with the fortune from the diamonds.