Louisa Young and her daughter Isabel Adomakoh Young, who write together as Zizou Corder, had huge success with their first book, Lionboy. Their fifth collaboration, Halo, is a funny and fast-moving adventure set in ancient Greece.

The story begins with a baby being washed ashore on a beach on Zakynthos, one of the larger Ionian islands, famous for its pulsating resorts packed with sunburnt Brits. Luckily for the little girl, she's 2,500 years too early to meet any of them. Instead, she's found by one of the locals, a centaur, and taken back to his tribe.

The centaurs, half human and half horse, live undisturbed in the hilly north of the island and don't have much experience of people, but they decide to keep the baby anyway. They name her Halosydne, quickly abbreviated to Halo, and rear her alongside one of their own children, a toddling centaur named Arko.

A decade later, Halo and Arko are swimming in a secluded cave when they are trapped by fishermen. Arko escapes, but Halo is caught, kidnapped, sold into slavery and taken to the mainland, where she embarks on a picaresque journey with two contradictory aims: to rejoin her adoptive family of centaurs and discover her real identity.

Halo soon learns that "no one has any respect for women, let alone girls", and decides to disguise herself as a boy. Stealing a man's knife and cloak, she plunges into a breathless series of adventures: she is schooled by the Spartans, defects to the Athenians, trains as a doctor, learns archery, witnesses a plague, travels from one end of Greece to the other, finds her family and even has time to fall in love.

The novel has flaws: the plot is episodic and too reliant on a string of unlikely coincidences; characters are introduced, then forgotten and discarded; the ending is rushed. But these irritations are swept aside by the  energy of the writing and some great set pieces, the best being a wonderfully vivid description of the oracle at Delphi.

The book is crammed with a multitude of real and invented characters, and oozes geeky information about the ancient Greeks. (Some notes at the back even explain how to make a bow or bake baklava.)

It will undoubtedly inspire young readers to learn more about the period, although they may be disappointed to discover that Pericles never really met a centaur.

Josh Lacey's novel Three Diamonds and a Donkey is published by Scholastic.