2010’s young adult novel I Am Number Four introduced us to the Lorien Legacies series, charting the struggle between the Mogadorians (boo-hiss baddies) and the numerically named Garde (teenage good guys with latent super powers who can only be killed in order of their numbers), both of whom have infiltrated Earth for reasons of destruction or survival. Written by Pittacus Lore (technically James Frey and Jobie Hughes) it’s a good concept for a series, starting with a fairly standard good guy/bad guy setup in the vein of Transformers’ Autobots vs Decepticons backstory, where the protagonists end up marooned on Earth facing an against-the-odds battle to survive and hopefully rebuild their world. Despite having spawned a critically-maligned film version the book series is still going strong, with The Fall of Five being the (confusingly) fourth novel in the series so far.
