Grainne was the daughter of the High King Cormac MacAirt, her stunning beauty was legendary across the island. Many high ranking nobles and chieftains tried in vain to secure her hand in marriage.
Enter our familiar hero, Fionn MacCool, leader of the Fianna warriors. At the time of the telling of the tale, Fionn is an aged man in the latter stage of life. He sought to marry Grainne and make her is second wife. Being who he was; the mighty Fionn of the Fianna who ate of the salmon of knowledge and whose feats had been immortalised by the great bards, Grainne agrees to marry him.
A great celebratory feast was held to honour the soon-to-be wedded couple. However, fate would have a hand in events that night, for it was here that Grainne and Diarmuid first laid eyes on each other.
Diarmuid was a young warrior, one of Fionn’s best fighters, handsome and strong, loyal.
Grainne was instantly entralled, she craved him and knew in that moment that she loved him. She knew in her heart that Diarmuid, not Fionn, was the right man for her and she decided to be with him. To get Diarmuid alone to herself she drugged the entire congregation with a magical potion sending all into a deep slumber. All except Diarmuid.
Alone, Grainne confesses her love for him but the loyal warrior refused to betray is leader, teacher, and friend, Fionn. This did not stop Grainne who was determined to get the man she truly wanted to be with. So she cast a spell on Diarmuid who falls deeply in love with her. The young couple depart the assembly under the cover of darkness and begin a life on the run.
Furious, Fionn and his men pursue the lovers across the island, but, helped by the young love god Aengus Óg, they remain elusive by making use of Irelands nooks, crooks, caves, trees, and crannies.
Traversing the island trying to avoid capture by Fionn and his Fianna warriors, running by day, sleeping under stars by night, using dolmens as their nightly bed, Aengus Óg gifted Diarmuid with a sword, advised the lovers on the best paths to follow and used his protective cloak to help the fated couple avoid detection.
They evaded capture for many years, but live like fugitives in their own lands. Always hiding, always moving, always in love with one another. After a time Grainne becomes pregnant with Diarmuid’s child.
But they couldn’t run forever, soon they would be confronted with the consequences of their actions when Fionn’s men finally finds them.
It had been prophesised that the boar was the only animal that would cause Diarmuid harm and that he should be weary around them. When they are confronted by a boar while crossing Benbulben in Co. Sligo, and with Fionn’s warriors closing in on them, they were panicked.
Diarmuid tried to kill the boar and protect his lover and unborn child by wrestling it to the ground as it charged for him. Diarmuid drove the sword which had been given to him by Aengus into the flesh of the boar, but not before it managed gorge a deep wound into Diarmuid. A wound that would be fatal.
Fionn and his warriors find Diarmuid and Grainne in this state. Grainne holds her dying lover in her arms, her robes covered in blood as she cries out for mercy. She reminds Fionn of the closeness of the friendship he an Diarmuid once enjoyed and begged Fionn to save him by allowing Diarmuid drink water from Fionn’s magical hands (remember, Fionn burned his finger on the Salmon of Knolwedge and gained magical abilities).
Fionn, stubborn and ignorant, bitterly refuses to listen to Grainne’s pleas. Diarmuid’s comrades of the Fianna could not stand to watch one of their own suffer like this, despite his wrongdoings, and they begin to emplore Fionn to help.
It is only when Fionn’s son Oisin challenges his father to fight if he does not help Diarmuid that Fionn acquiesces. Cupping his hands at a nearby stream, Fionn ran to Diarmuid but, alas, it was too little too late.
Diarmuid had died and Grainne was devastated.
