Landlords the world over are not the most popular people, and there is little morning when the greedy, ruthless Mahendralal Bakhle is blown up on his boat on the beautiful Periyar Lake. Suspicion falls on the boat-boy who died with him, but Dominic Felse, one of a party of young tourists accidentally involved in the fatality, is not convinced of the boy's guilt. And when they move on, it seems that the terror is still pursuing them.

At the monastery in Shrewsbury in 1138, the gardens are flourishing under the expert tending of Brother Cadfael. His workshop boasts all sort of medication for every kind of ailment. Then one Gervase Bonel, who had planned to leave his valuable manor house to the Abbey in exchange for a house run by the monks where his comfort will be guaranteed for life, is poisoned with Cadfael's own concoction intended for aching joints. As the monk investigates he finds a web of family intrigue, where suspicion has fallen on someone he is certain is innocent.