Irish title for the narrative known in English as The Voyage of Máel Dúin's Boat; also Imram Maíle Dúin, The Voyage of Máel Dúin. Although probably composed in the 8th century, the story survives in 10th-century fragments in the Book of the Dun Cow, the Yellow Book of Lecan, Egerton ms 1782, and Harley ms 5280.
Máel Dúin is the love-child of a nun, fostered by a queen and three princes. In a taunt one day he learns both of his illegitimacy and that his father, Ailill Ochair Ága [edge of battle] has been killed by raiders. Not knowing how to avenge him, Máel Dúin consults a druid, who tells him to build a boat of three skins and to take only seventeen companions. He sets about following this advice when three foster-brothers swim out to join, portentously violating the druid's geis. They voyage all day until midnight before they land on the first two of what are to be thirty-one islands, each the site of a fabulous adventure. These include massive ants and birds, a beast who can turn his skin round like a mill, demon horses, fighting horses, and a cat guarding treasure who can turn men to ashes. One island is divided by a brass wall, with black sheep on one side and white on the other. Some of their discoveries are happier, like the severed branch of the apple tree that satisfies the crew for forty days. Most often, though, they face dangers, both aggressive and seductive. On one island stones are thrown at the currachs as the men make their escape. On the Island of Smiths, a red-hot iron bar comes flying their way and sets the entire sea to boiling. A primal chorus draws travellers against their will on the Island of Laughter and the Island of Weeping. On the Island of Women the queen warmly greets Máel Dúin, offering her seventeen daughters as bed-partners to the crew. Offering the men uninterrupted pleasure and perpetual youth, she induces them to stay forever, but after three months they try to return to their boat. She throws a ball of thread after them, magically preventing them from leaving; three times she holds them back for periods of three months each. On the fourth attempt the crewman and poet Diurán catches the thread and then allows his arm holding it to be severed, allowing them all to escape.
Often the narrative employs surreal imagery, suggestive of the Otherworld, like seas of green glass, intoxicating fruit, silver nets, silver columns, and an island on a pedestal with a door at its base. Máel Dúin and his crew, Diurán and Germán most prominently, are driven with vengeance as their quest. At a turning-point in the narrative, however, they encounter an old monk, clothed only in his own overgrown hair, who says he is a survivor from the time of St Brendan of Birr (d. 565 ad); he asks them to forgive the slayer of Ailill Ochair Ága. They agree, and in due time reach the island of their former enemies, where they are made welcome. After telling the story of their wanderings, Máel Dúin and his men return to Ireland.