It tells the stories of young adventurers in the Traction Era, when moving cities roam the wasteland, attacking and devouring each other for resources.

[6] A companion piece entitled The Traction Codex was released in 2011, and was expanded into The Illustrated World of Mortal Engines by Reeve and Jeremy Levett and published in 2018.

[7] However in February 2024, Reeve announced the creation of a new Mortal Engines standalone prequel novel, entitled Thunder City, would be released later in the year.

They discover that Valentine salvaged an ancient weapon called MEDUSA, which the Guild of Engineers has reassembled inside St Paul's Cathedral.

They are soon pursued by the Green Storm, a fanatical splinter group of the Anti-Traction League, who seek the Jenny Haniver, which they believe was stolen from their deceased leader, Anna Fang.

Tom also discovers that the "ghosts" are actually thieves operating out of a parasitic submarine-like limpet attached to the bottom of the city, who call themselves the Lost Boys.

Freya catches Pennyroyal secretly broadcasting a radio message requesting his rescue, and he admits he lied about traveling to America.

Meanwhile, Pennyroyal escapes to the Hunting Ground and publishes a book reimagining his time in Anchorage with himself as the hero, and Arkangel is evacuated and eventually sinks to the bottom of the ocean.

Sixteen years later, most inhabitants of the now-static city Anchorage-in-Vineland are happy with their new lives, except Wren Natsworthy, the teenage daughter of Tom and Hester.

One night, she encounters three Lost Boys—Remora, Fishcake, and their older leader Gargle—who have come to Anchorage in search of the Tin Book, an artifact that contains the activation codes for orbital weapons left over from the Sixty Minute War.

Devastated, Fishcake kidnaps Wren with the intention of taking her to Grimsby, but changes course after receiving an enticing communication from the raft resort of Brighton.

Nabisco Skhin, owner of the slave trade company, interrogates Fishcake, who reveals the location of Grimsby, prompting Brighton to destroy it with depth charges.

Uncle is killed, and Tom and Hester leave to find Wren, whilst Caul and Freya return to Anchorage with the remaining Lost Boys.

At Fang's command, the Green Storm armies extend their borders, starting a war with the Traktionstadtsgesellschaft, an alliance of German-speaking cities.

Wren and Theo are captured by General Naga, Green Storm's second-in-command, and brought before Fang, who takes the real Book and memorizes the codes.

Hester, Theo, and Shrike also arrive, and discover Pennyroyal hiding in Airhaven in disgrace and debt after a newspaper exposed him as a fraud.

Stalker-birds attack the Jenny Haniver; Shrike falls out, and the airship downs near Fang's old home, where Hester and Tom leave Pennyroyal tied up.

She explains that she intends to command ODIN to target volcanoes around Earth, which will erupt and trigger volcanic winter; this will kill humanity but "make the world green again".

A few of the people in the books are named after places in Devon, where Reeve lives, including Chudleigh, Tamerton Foliot, and the River Plym.

[9] Many of the characters are named after ancient (in the context of the books) brands: Windolene Pye, Daz Gravy, Nutella Eisberg, Napster Varley, and Nabisco Shkin for example.

The series is set thousands of years in the future in a time known as the Traction Era, in which Earth has been reduced to a wasteland by a devastating conflict known as the Sixty Minute War.

Nations no longer exist except in the lands of the Anti-Traction League, whereas Traction Cities—mobile cities often mounted on caterpillar tracks—are fiercely independent city-states that use giant mechanical jaws to dismantle one another for resources.

All Traction Cities consist of several 'tiers' fixed to a huge hull containing engine rooms, storage hangars, and a large "gut" where captured towns are dismantled.

A powerful remnant of the Sixty Minute War, it was built as part of the arms race between the American Empire and Greater China.

The Tin Book, copied from a US Military document recovered via submarine by the refugees of the original Anchorage, is a codebook for controlling ODIN.

This, as well as the Stalker minds found among Old-Tech (and Shrike), seems to prove that robots had, by the time of the Sixty Minute War, achieved sentience.

The Traction Codex is a fictional reference book set in the world of Mortal Engines, written by Philip Reeve and Jeremy Levett.

In the Bleak Midwinter is a short story written online by Philip Reeve and Sarah McIntyre, following the young Hester Shaw and Shrike aboard the town of Twyne.

[12] It stars Hugo Weaving, Hera Hilmar, Robert Sheehan, Jihae, Ronan Raftery, Leila George, Patrick Malahide, and Stephen Lang.

[14][15] In an interview with Polygon on 30 October 2018, producer Peter Jackson explained an absence of a game based around the 2018 Mortal Engines movie, saying if that film performs well enough to make a sequel, there will definitely be a videogame to follow.