Ada and the Singing Skull

Even before things can settle down to the expected calm of a bucolic countryside, another mystery drops into Frederick Bisset's lap. This time it involves a skull, its presence in an otherwise pretty and snug cottage revealing a history of madness and its macabre effects on a mother-daughter bond. The cottage's present owner, Ada Darrow, is an aging spinster, an intellectual who suffers neither fools nor supernatural shenanigans, and she willingly takes on Freddy and Jonathan's (unpaid) help in sending otherworldly energies away and past the veil-thing.
However, such an endeavor is easier said than done because the skull doesn't seem to want to cooperate, satisfied instead in filling random hours in the cottage with off-key singing. It will take Freddy more than luck to see through a successful completion of this case.
In the meantime, a terrible disaster upends life in St. Grimald Priory: Mr. Brummell, Nicodemus, and Nero the Mad have vanished, and there are no clues shedding light to the cats' whereabouts. And nothing -- absolutely nothing -- will keep Prudence Honeysett from turning the countryside inside out to retrieve her beloved mousers. Elsewhere, family drama keeps everyone on their toes when Lucinda hares off for a fortnight spent with friends and spiritualists, leaving the men of her family sorting out their own haunted mystery at home.
Humorous letters and journal entries continue to recount more inconvenient misadventures in otherwise idyllic Hoary Plimpton.