Once upon a time, Crimthann Cas being their king then, Connacht were in convention by énloch or 'bird-loch' in Magh nAei or 'the plain of Aei.' On the night in question they remained assembled and, when on the morrow they were risen betimes, saw a man that came through the mist and towards them: a mantle of five folds he wore, and in his hand were two five-barbed darts; a gold-rimmed shield was slung on him, at his belt was a gold-hilted sword, and golden-yellow hair streamed behind him.
"Give welcome to him that comes to you!" cried Laeghaire Líbhán son of Crimthann, the noblest young man that was of Connacht namely, and: "a welcome to the warrior whom we know not!" he said to the stranger, who made answer: "I thank you all."
"Wherefore comest thou?" Laeghaire enquired, and the other said: "to crave a force of men."
"Whence art thou?"
He replied: "of the men of the sídhe I am; Fiachna mac Retach is my name, and the matter is that my wife is taken from my head [i.e. pillow], Sál's son Eochaid having carried her away. He then in a pitched battle being slain by me, she is gone to a brother’s son of his: to Dalbh's son Goll, that rules the fort of Magh Meall. Seven battles I have given him, but all are gone against me; for this very day yet another one is declared by us, and to solicit help it is that I am come. To every man moreover that shall desire it I will in lieu of his coming with me give a fair sum of gold, and of silver the same."
With that he turned and went from them.
"Not to aid yonder man were a shameful thing," Laeghaire said, and together with fifty fighting men stepped out after him who, still preceding them, dived down into the loch, and they followed him.
There they saw before them a strong place, and a company embattled that stood face to face with them. He, Fiachna mac Retach, went on yet in front of them and to his own hold, where they saw two companies.
"Verily it is well," said Laeghaire: "I to the number of fifty warriors will engage with the chief on the other side."
"I will answer thee," said Goll son of Dolbh.
In their two fifties therefore they laid on each other, and [in the end], after the fall of Goll and of all his fifty, Laeghaire with his escaped alive. Then 'the battle broke before them,' and they made general slaughter of their enemies.
"Where is the woman?" Laeghaire asked; and Fiachna said: "within in the dún of Magh Meall, surrounded by a force."
"Bide ye here while I and my fifty go," Laeghaire said, and proceeded to the fort. They set about taking it, and he called [to the defenders]: "but little 'twill profit you [to hold out]: your king is fallen, your nobles are slain; suffer then this woman to come forth, and in return your safety shall be accorded you."
So it was done and, as she came out, she pronounced [that which is known as] 'the lament of Eochaid Amlabar’s daughter.'
Laeghaire returned with her and laid her hand in Fiachna's; that night Fiachna's daughter Der Gréine or 'maid of the sun' was coupled with Laeghaire, and with his fifty laechs fifty other women, and to a year's end they abode with them.
Laeghaire said then: "let us go seek tidings of our land."
"If ye would come back," Fiachna enjoined, "take with you horses, but by no means dismount from off them."
So it was done: they went their way and came upon a general assembly in which Connacht, as at the year expired, mourned for the aforesaid warrior band, whom now all at once they perceived above them [i.e. on higher ground].
Connacht sprang to meet them, but Laeghaire cried: "approach us not [to touch us]: 'tis to bid you farewell that we are here!"
"Leave me not!" Crimthann, his father, said: "Connacht’s royal power be thine; their silver and their gold, their horses with their bridles, and their noble women be at thy discretion, only leave me not!"
But Laeghaire turned from them and so entered again into the sídhe, where with Fiachna he exercises joint kingly rule; nor is he as yet come out of it.