This is Toby Frost's best yet. Isambard Smith and his crew take on the Lemming men who are sworn to destroy him when not being distracted by great heights from which they can't help but throw themselves. This story has more sub plots and it is told from more points of view. The characters have filled out and true friendships are growing. The constant nods to other sci-fi stories are now joined by references to Thomas the Tank Engine, The Chipmunks and Watership Down. His last book (God Emperor of Didcot) was good, but the humour was a little stilted at times, but in this book, it's flowing freely again. The relationship between Smith and the hippy Rhianna Mitchell is more realistic and there's basically more to get your teeth into while still being outrageously funny.