The Reluctant Assassin is the first book in the W.A.R.P. series. W.A.R.P. stands for 'Witness Anonymous Relocation Programme'. The assassin of the title is young Riley who has been apprentice to Albert Garrick, a Victorian illusionist who has fallen on difficult times and taken to using his unique conjuring skills to gain access to victims' dwellings. On one such murderous escapade he brings his reluctant apprentice along on his first killing. Riley is saved from having to commit the grisly act when the intended victim turns out to be a scientist from the future, part of the FBI's W.A.R.P. program, and Riley is transported to modern day London, followed closely by Albert Garrick.
In modern London, Riley is helped by Chevie Savano, a nineteen year old FBI agent sent to London as punishment following a disastrous, undercover, anti-terrorist operation in Los Angeles. Together they must evade the assassin, Albert Garrick, who has been fundamentally altered by his trip through the wormhole. Garrick is now more than human and is determined to track Riley down and use the timekey in Chevie's possession to make his way back to Victorian London where, with his new knowledge on all things scientific and technological, he can literally change the world.