Role in the film
When Robin Hood wishes they had a priest to join them, look after the wounded, and care for the poor, his new member of his Merrie Men, Little John mentions a churchman hermit he knows by the name of Friar Tuck who lives in Alford Abbey.
Near the abbey, Friar Tuck is seen drinking wine, eating capon pie, talking, and singing to himself until Robin Hood gives himself away when Friar Tuck hears him singing to his tune and catches him behind the tree the Friar was sitting under; thinking he was spying on him. The two men later force each other to carry one another on his back to get them across the stream and then have a little duel until they are ambushed by the Sheriff of Nottingham and his men. When Friar Tuck defies the Sheriff and refuses to allow him and his men to deal with Robin Hood since he's not done with him yet and cares about him, a battle ensues between both parties. During the battle, Friar Tuck is rendered unconscious by the Sheriff. Outnumbered, Robin calls for his men and they succeed in killing the Sheriff's men. When Friar Tuck regains consciousness and catches the Sheriff trying to escape, he calls out his dog with a whistle to attack and hold him. Then, Robin and his men capture the Sheriff himself, who was being molested at the time by Friar Tuck's dog as he tried to escape.
Robin, his men, and the Friar take the Sheriff (blindfolded momentarily) back to Robin's lair in Sherwood Forest where they force him to eat and drink to the good health of their King Richard, pay the taxes for all the troubles he caused (including the ones he inflicted on his two former prisoners) through Friar Tuck's calculations, and later, send him off blindfolded again while riding his horse the other way around back to Nottingham Castle in order to give courage to the poor the Sheriff has persecuted.
Two years have passed, King Richard's Crusade has ended in failure, and the King finds himself imprisoned in Austria to be held for a ransom of 100,000 marks.
Maid Marian, Robin's childhood playmate, and love interest leaves the castle, disguised as a page boy to find Robin Hood in Sherwood Forest to convince the Queen Eleanor of Robin and his men's loyalty and honesty since Prince John has convinced his Queen mother and the Archbishop of Canterbury otherwise. During the journey, she is joined by Allan-a-Dale the minstrel and Midge the Miller. Once at Sherwood Forest, they encounter Robin Hood, Little John, and Will Scarlet. The outlaws make Midge pay some money and Allan-a-Dale sing a tune while Marian tries to stop them. Robin is delighted when he finds out that the page boy is none other than Maid Marian and decides to bring her and her friends back to their lair. Knowing of the Prince and the Sheriff's lies and treachery, Robin and his men including Friar Tuck generously and honorably donate as much money as they can to pay the ransom and ensure the King's safe return. As Robin Hood and Friar Tuck take Maid Marian back to Alford Abbey for the night, Robin and Marian share a kiss after Robin helps her cross the stream as Allan-a-Dale joins along to sing a love song for them; much to Friar Tuck's delight.
The next day, during the donation at Nottingham Square, after being escorted by Friar Tuck, Maid Marian presents everyone with Robin Hood and his men's donations; much to Prince John and the Sheriff's chagrin and the Queen and the Archbishop's joy.
A few days later, after foiling Prince John's plans involving the King's ransom money and vanquishing the Sheriff for good, at Robin's lair, Robin Hood is wounded and sick, thus, forced to reluctantly stay in bed in a cave and eat broth and barley at Friar Tuck and Maid Marian's insistence. Then, a mysterious black rider appears. The rider says he seeks Robin Hood, thus, making Robin Hood suspect he could be one of Prince John's men and then forcing the rider to take off his hood. Even Friar Tuck threatens to hurt the rider with his staff if he refuses otherwise.
To avoid misunderstandings, the rider reveals himself to be in fact, King Richard, whose ransom has been paid and who has returned safely to England. Not wanting his apology for his rash behavior and indebted to his good deed and that of his men, King Richard knights and dubs Robin, the Earl of Locksley. When King Richard spots Maid Marian, wearing an outlaw's disguise, he tells her that her father awaits her at Huntingdon where the Queen vows to marry her to the Earl of Locksley. At first, Marian seems shocked since she remains oblivious to the fact that Robin Hood is infact the Earl she is to marry until the King reveals him to her.
Friar Tuck and the men watch Robin and Maid Marian share a kiss as they prepare to be married.