Enola Holmes—international bestselling and Netflix streaming sensation—returns when the rescue of a young woman sends her into battle with her brother Sherlock against his most deadly, implacable enemy - Professor Moriarty.

In February 1891, London, Enola Holmes—the much younger sister of Sherlock and Mycroft Holmes—is attending a burial when she hears the faint sound of a handbell in the graveyard. It is not in Enola’s nature to ignore such oddities, no matter the occasion and when she investigates further, as is the Holmes' family instinct, she discovers something absolutely chilling. The ringing bell is attached to the tombstone erected over a recent gravesite and someone, buried within, is pulling the string to ring the alarm.

Galvanized into action, Enola and her companions swiftly and successfully unearth the coffin within, freeing a still-living young woman, one Trevina Trairom. Enola, by predilection and by trade a Scientific Perditorian, a finder of lost things, finds herself comforting and protecting this young girl. The girl herself is a mystery – she remembers very little, including her identity, and has no idea who has buried her alive, much less why. While protecting this mysterious girl from an enigmatic enemy, she discovers that Sherlock is engaged in a related mystery. Enola joins Sherlock in his battle against the scourge of London, the Napoleon of Crime himself, Professor Moriarty. Facing her most brutal foe ever, determined to protect and unravel the secrets surrounding the mysterious Trevina, Enola takes her place more fully than ever as a proud member of the Holmes family.