A horrified Robin realises that his plan to capture the Sheriff's spy, Henry of Lewes, has failed because he has a traitor in his gang. Fearing for Marian's safety in the castle, Robin sets about rooting out the turncoat. His only clue is supplied by Marian: the spy's meeting place is located at the Trip To Jerusalem Inn, where the traitor outlaw sells his secrets to Gisborne.
With two missions to complete Robin is relieved when Henry of Lewes arrives at the castle unconscious, his vital information about the King's landing sites remaining a mystery. Robin infiltrates the castle to silence Henry, but help arrives in the shape of harridan wise-woman Matilda, tasked by the Sheriff to nurse Henry to health. Asking Robin to look after her heavily pregnant daughter, Matilda promises that she'll silence Henry using special herbs, but doesn't bargain upon the Sheriff making the connection with Robin Hood and putting her life in mortal peril.
Robin returns to the forest with Matilda's daughter, to a confused and hurt gang: they resent being suspected of treachery and it takes all of Robin's leadership skills to rally his outlaws into helping Rosa.
But then Marian arrives reporting that Matilda is about to be tried for witchcraft. The race is on to rescue her before she drowns. Can Robin trust his gang to save the lives at stake as well as silencing Henry? As Robin well knows, there is a spy in his gang who needs catching before this day is out. Robin hits Will and chases him away as a decoy, and then goes to the inn, where he finally finds the real traitor, Allan. Although he doesn't kill Allan, Robin does banish him from the gang.