These characters spend their A Clash of Kings time hanging out in the Seven Kingdoms's capital, King's Landing. Since Joffrey's rule began, it hasn't exactly been the relaxing vacay hotspot it once was. Still, this is where you'll find these folks:
Ser Cleos is captured by Robb during the Battle of the Whispering Woods and then sent to King's Landing with Robb's terms for peace. When he gets there, Tyrion disapproves of the terms and sends him back with new terms—and a couple of guys to prison break Jamie. Although he knew nothing of the foiled breakout attempt, Ser Cleos is imprisoned again, thus ending his career as a negotiating ping-pong (46.Catelyn.58).
Ser Dontos Hollard use to be a knight but a small incident on Joffrey's name day involving a horse and no pants ends that career path. After Sansa convinces Joffrey it would be bad luck to kill a man on his name day, the young king decides to make Ser Dontos a court jester instead (3.Sansa.62). Afterward, Dontos meets with Sansa in secret in the godswood, claiming he is plotting to help her escape King's Landing in exchange for her kindness in sparing his life. Sansa might have a little more confidence in him if he were a little less drunk when they meet, though.
Tyrion thinks of the recently knighted Ser Lancel as the kind of boy who is "wed to the arrogance that [comes] so naturally to those born blond and strong and handsome" (26.Tyrion.4). When Tyrion discovers that Cersei has taken Lancel as a lover, Tyrion blackmails the young man to be his informant. Lancel confesses he provided Robert extra strong wine on the day of his death, and a lot of it, but the boar did the actual killing (30.Tyrion.28).
Hallyne is the head of the Alchemist Guild. His fellow alchemists craft the wildfire used in the Battle of the Blackwater, and they have also been discovering mysterious caches of wildfire left all over the city by King Aerys.
Tanda Stokeworth is the head of House Stokeworth and the mother of Lady Falyse and Lady Lollys. Tanda attempts to play matchmaker between Tyrion and Lollys, whom Tyrion views as a "large, soft, dim-witted girl" (18.Tyrion.41). Lollys is later raped and becomes pregnant during the riots in King's Landing (42.Tyrion.91). Major bummer for her. All three are brought to the Red Keep during the Battle of the Blackwater.