Luke Reader is the triplet brother of Gideon Reader and Catherine Reader. He looks like Gideon, but with glasses, and used to live with his foster mother on the Isle of Wight. At first, Dax is jealous of Luke because of all the attention Gideon gives him, but he forces himself to respect the newcomer, and tries to accept that 'Gideon and Dax' was going to become 'Gideon and Dax and Luke'.
He first appears in Running the Risk, at Tregarren College. He is considered a "dud", not exhibiting any supernatural powers, except for an incident in the dormitory, where he breaks the glass in the window by accident with his mind. Nobody realises it was him except Dax. He then shows his powers at the end of Running the Risk, by holding a wave with his mind, one that Catherine would have used to destroy the other Colas, thus saving them. He then lets the wave crash down, and Catherine takes him away with her.
He is a telekinetic like Gideon, but to a far greater extent.
In Dowsing the Dead, when the Colas find Luke again, they realise that he is mute, as Catherine has somehow shut down the speech centres of his brain, rendering him mute.
When Catherine takes Luke away, she goes to Nice, and emprisons him there.