When Lily’s deportment teacher confiscates the magazine she’s reading telling her it has no educational value at all, Lily replies, ‘It teaches piracy and air combat.’ ‘And what young lady needs to know that?’ asks her teacher. Actually it turns out this is exactly what Lily needs to know.
This is a steam-punk world – Victoriana with airships, and mechanical talking servants and animals. When her father’s airship is attacked and death seems imminent, he asks his ‘mechanimal’, Malkin, to deliver a letter to his beloved Lily and tell her ‘the secret’s in the safe’. Malkin is chased and nearly fatally injured by two mirror-eyed baddies, but luckily he’s saved by clockmaker’s son, Robert. Together Malkin and Robert make sure Lily receives the letter, albeit in a damaged form, and the message.
Lily manages to retrieve a locked box from the safe in her home before the baddies catch up with her. She soon guesses it contains the perpetual motion machine – the Cogheart of the title. It must be very valuable because everyone’s after it, and Lily, Robert and Malkin are chased all over the place. It’s quite a shock to find out what the Cogheart does, and where it actually is.
Lily is a cheery heroine who makes the best of things even when she finds out her father’s terrifying secret. She doesn’t let Robert dwell on his father’s sad demise, and has little sympathy for his fear of heights. It’s an enjoyable, fast-paced romp, and rather fittingly for a book containing so much clockwork, it reaches a climax on Big Ben.