The Running Bride - S4.E6

Robin escorts Princess Margaret of Scotland to England to marry the English Prince Harry Glossmore. But the Duke of Wellington and the Earl of Grimsby want to stop the union, to further their own ends, so Robin has to protect her from their would-be assassins. Meanwhile, Marion, Little John and Andy discover the Duke is persuading Harry's younger brother to poison Harry so that he can accede to the throne. Robin safely brings the princess to Harry's castle and thwarts the plan.