When Robin discovers that the Black Knights are descending on Nottingham to sign an insidious pact against the King, he turns to Lord Winchester as his only hope. With Winchester on-side and ready to stand upto the Sheriff, Robin thinks the job is done - until he realises, to his horror, that Winchester is corrupt. Robin must steel himself to make the ultimate sacrifice for England.

Marian's arrival in the gang distracts them from detecting the Sheriff's infiltrator in their midst. As Carter the assassin strikes his deadly blow, Robin discovers he's concealing another secret - revenge forhis dead brother. Rather than punishing the murderous assassin, Robin wins him over and persuades him to turn the tables on the Sheriff.