The number in the first column represents the episode's number overall, whereas the number in the second column indicates the episode's number within this particular season. "U.S. viewers in millions" refers to how many Americans who watched the episode live or on the day of broadcast.
Production
The show's creator Eric Kripke originally planned for the show to last only five seasons, but due to increased ratings from the fourth and fifth seasons, the CW network renewed the series for a sixth season. Kripke did not return as showrunner; however, he remained a hands-on executive producer, leaving long-time series writer Sera Gamble to take over the day-to-day production of the show. Filming for the season began with the series star Jensen Ackles-directed fourth episode, "Weekend at Bobby's", to give the actor enough time for pre-production. Kripke also wrote the season finale. , who worked on Supernatural since its first season, took over as showrunner for the sixth season. Gamble said the sixth season of the show would focus on the brothers' relationship. The season steered towards the format of the early seasons with "lots of meat-and-potatoes closed-ended episodes, and... a season-long story arc to weave in". According to a press release by the CW, Heaven and Hell fell into "complete disarray", forcing Sam and Dean to reunite to "beat back the rising tide of creatures and demon-spawn" that "roam across a lawless and chaotic landscape". The season jumped ahead a year to "get some distance between , get some personal history for each of them" to allow for "new conflict, new circumstances, new stuff". The brothers' roles were reversed, with Dean now hesitant to return to the hunting lifestyle. The brothers investigated why monsters have been "acting off-pattern". The first few episodes establish the mythology. An episode spoofing Twilight and other vampire series aired in October 2010 and examined the "current romantic fascination" with vampires. However, the Twilight fans at the center of the Winchesters' "disparaging" comments were "slightly fictionalized". On this, Gamble noted, "...part of the thing is finding a balance between a poster from the actual show and having Sam and Dean really speak their minds. We don't want to offend." A fan of the Twilight series, she also commented, "I'm certainly not coming at this from a place of feeling superior to them. I have great respect." Another episode of the season, "Clap Your Hands if You Believe", consisted of an "insane" storyline featuring Tinker Bell, and the episode began with an alien abduction and a redone title sequence that is a tribute to The X-Files. Misha Collins returned as series regular Castiel, and Jim Beaver returned as Bobby Singer for several episodes. Mitch Pileggi made multiple appearances as Sam and Dean's grandfather Samuel. The recurring role of Christian, the maternal cousin of Sam and Dean, was given to Corin Nemec; he was described as "capable, calm under pressure, and very good at his job". Kim Rhodes returned as Sheriff Jody Mills, as did Fredric Lehne as Azazel. A two-hour season finale aired on May 20, 2011.
