Sleepy is an original novel written by Kate Orman. It features the Seventh Doctor, Bernice, Chris and Roz. It is part of the "Psi Powers series".
The earth colony Yemaya 4 is struck by a plague that causes the colonists to manifest psychic powers. The Doctor and his companions become heavily involved. Some of the group contract the plague, while others travel back in time to try to find out how it started. Meanwhile, murderous agents threaten to simply kill every innocent person involved.