British comic writer M.R. Carey dazzled in 2014 with The Girl With All The Gifts, a rare literary foray into the pulpy subject of zombies.

He returns with a worthy prequel, The Boy On The Bridge, which eschews the twists of its predecessor for a more considered perambulation through the same fascinating post-apocalyptic universe.

Readers of the first book will know that the apocalypse was caused by the cordyceps fungus which, in a particularly aggressive pollination exercise, has been spreading a pathogen that turns humans into mindless, ravening "hungries".

Evolution, however, has produced a kink. The children of "hungries" too crave flesh, but retain intelligence. Forming their own tribes in the wild, they are a deadly force to be reckoned with.

At the end of The Girl With All The Gifts, readers encountered the Rosalind Franklin (Rosie), an armoured mobile laboratory abandoned on a London street.

In this prequel, one finds out how Rosie got there. The novel opens with the vehicle midway through a research trip into the treacherous countryside. On board are the scientists collecting samples for Beacon, the last headquarters of a crumbling government, and the soldiers tasked with keeping them alive.

There is no love lost between these two groups, particularly between toadying head scientist Dr Fournier and military leader Colonel Carlisle, also known as "The Fireman" because of the burn runs he led that fried civilians during the first wave of infection.

One of the scientists, epidemiologist Samrina Khan, has a secret: She is pregnant, against mission regulations, in the worst possible environment to bear a child.

She already has a charge: Stephen Greaves, a 15-year-old prodigy who survived a massacre in which he watched his parents get eaten as they shielded him with their bodies. He could be the key to discovering the cure to the virus - that is, if he can get past his dire social anxiety to tell someone his findings.

Carey's gift for complex characterisation is on full display here. The scientists are led by emotions as much as empiricism; the soldiers are more than cold-blooded killers.

In a short span of time, the reader comes to know and care about the people inhabiting the confines of Rosie - which is unfortunate because soon, the bloodletting begins.

On a reconnaissance mission in a ghost town, Rosie's crew runs afoul of a tribe of preternatural kids who are soon hunting them cross-country, Children Of The Corn-style.

Mixing up gripping action scenes and gallows humour with grave moral questions, Carey takes a good, long look at what people do with their humanity when the world falls apart.

If you liked this book, read: World War Z by Max Brooks (Broadway Books, 2007, $27.72, Books Kinokuniya), a faux oral history of how the world succumbed to the zombie apocalypse.