Nothing's been the same since Bun Bendle dived off a quay and hit his head on a rock. What he can't bear to tell anyone is that as well as his sight, the accident seems to have wiped out parts of his memory. In despair, he contemplates suicide, but the love of his great friend Anna saves him. His friends petition for him to be able to stay on his home island of Bryher in the Scilly Isles, and not be sent away to school. Calling his father in for tea one day, Bun falls through a cavity under the field. His father's tractor rumbling towards him just manages to stop, inches away. The cavity is a tomb, containing an ancient and beautiful sword and shield. Bun is immediately drawn to them, and as he holds the sword, Bedivere, a knight of the Round Table appears and commands him to take it to King Arthur.