This tale narrates the story of Conchobar's birth. His mom's foster family got killed and she went on a rampage, looking for the evil-doers (the main baddie was Cathbad). When she bathed one day in a river, the druid Cathbad saw her and almost killed her; in exchange for her life, Nessa married him and they had Conchobar.
Cathbad prophesied that the daughter of a local Irishman would be a heartbreaker; boy, would she ever. This turned out to be Deirdre, whom Conchobar wanted to marry—but, of course, she ran off with local heartthrob Naoise. Conchobar exiled them both along with Naoise's brothers, but he eventually caught them. When Naoise was killed and Conchobar was finally gonna marry Deirdre, she bumped her head and died.
Here's how it went down: Maeve of Connacht wanted a bull as handsome as her husband's, so she went after Conchobar's prized brown bull. Good ol' Cúchulainn beat up many of the Connachtmen that came their way—since most Ulstermen were incapacitated by a curse—but the bulls ended up battling each other. Even though Conchobar's brown bull won, he died of exhaustion.
This story's title is pretty self-explanatory. By the time Conchobar was seven, his mom was single; and King Fergus mac Roich of Ulster fell in love with her. In exchange for marriage, she forced Fergus to make Conchobar king for a year. But his mom had him give the Ulster councilmen so many gifts that they wanted him to stay king 4eva.
Maeve gets a pretty good write-up in this novel, and Conchobar's not looking too shabby himself.