The TARDIS lands in Paris on 19 August 1572. Driven by scientific curiosity, the Doctor leaves Steven to meet and exchange views with the apothecary, Charles Preslin.

Before he disappears, he warns Steven to stay out of 'mischief, religion and politics'. But in sixteenth-century Paris it is impossible to remain a mere observer, and Steven soon finds himself involved with a group of Huguenots.

The Protestant minority of France is being threatened by the Catholic hierarchy, and danger stalks the Paris streets. As Steven tries to find his way back to the TARDIS he discovers that one of the main persecutors of the Huguenots appears to be - the Doctor.

Novelization of the Doctor Who TV series; four episode story "The Massacre of St. Bartholomew's Eve" (1966), script by John Lucarotti and Donald Tosh.