A scientist's ten-year-old son dies, killed by eating food intended for his father's research rabbits. The man and his wife, Terence and Laurie Morton, then adopt another boy, James. But James is a weird, aloof child from the beginning, and shocking things happen around him. Dr Morton is a busy research botanist, and his wife works for charities, neglecting their new son - which is just as it was with William, the boy who died. James finds William's diary and reads a poem he wrote in it about his lonely life, and this calls up the dead boy. William's ghost invades the household, looking for revenge on his father and causing terrible events to unfold.