Background: For anyone not familiar with the Robin of Sherwood TV series, here's all the background you need for this story.
Merrie Men: Robin Hood (Robert, son of the Earl of Huntingdon), Marion, Little John, Will Scarlet, Nasir, Tuck and Much. Herne: Robin's mystical forest guide.
Baddies: Robert de Rainault, Lord High Sheriff of Nottingham; Abbot Hugo (his brother); Sir Guy of Gisburne, (his steward); King John.
Two Robins: Robert of Huntingdon is the second Robin Hood, the first (a peasant, Much's foster-brother and Marion's husband) having been killed by the Sheriff at the end of the second series.
The Big Secret: Sir Guy is illegitimate and his father is the Earl of Huntingdon. Only Robin Hood and Tuck know this. Guy and the Earl are both in the dark.
The Time of the Wolf: In this final episode of the Robin of Sherwood TV series, King John commandeered all the villagers' grain for his army, leaving them to face the prospect of starvation in the winter. Robin Hood successfully raided the granary and stole the grain back while it was in the care of the Sheriff. The Sheriff blamed Sir Guy who fled and was captured by a Norse cult called 'The Sons of Fenris', headed by the evil Gulnar. He elected to join them. They capture The Sheriff.
In an effort to defeat Herne, Gulnar creates a doppelganger of Robin. The two Robins fight and the evil one is killed. Marion sees the body and believing Robin to be dead, she takes refuge in the Abbey. When Gulnar is defeated the Sheriff and Sir Guy find the body of the fake Robin and take it to the King, but it turns back to clay.