Mid Season Wham Episode

So you've been watching a show for a few weeks now, you like the characters and are just getting comfortable with the routine of how things work. You tune in expecting another Monster of the Week when all of a sudden the writers pull a fast one.

This is done either give the audience just what they've been waiting for, raise the stakes, or change the game somehow to keep things more interesting.

Generally the point when the Exposition stops and the real plot begins. Usually falls on episode 7 or there about, as it's halfway through the first 13 episode season, or 1/4 of the way through your 26 episode season if you get renewed. May extend to later seasons as well.

Warning. Examples may count as spoilers, but since they're so early in the series, most are probably closer to You Should Know This Already.

Anime and Manga

 * Aquarion Evol: In episode 13 (halfway through the series).
 * Bomberman Jetters: White Bomber discovers  Shout's sad backstory is also explained and   These are in 23, 24 and 25, but to be fair, it's a 50+ anime series.
 * Just like the first Fullmetal Alchemist series. On episode 25.
 * Gundam Wing: The 5 Gundam pilots come together for the first time in the 7th episode.
 * G Gundam hits one episode earlier. Episode 6 is when you learn Domon and Kyoji's backstory and he activates supermode for the first time.
 * Digimon Adventure: Hit's one episode later, Devimon the first Big Bad makes his first official appearance in episode 8
 * Naruto: Episode 7 is when Zabuza is formally introduced, and the show jumps from being about a kid in ninja school to an A-rank protect against an evil assassin mission.
 * Gurren Lagann: Episode 8.  Nuff Said.
 * Chapter 7 of Magical Record Lyrical Nanoha Force sees the resident Lady of War Signum utterly and messily fragged by a newcomer villainess, establishing a much more gory mood of this manga compared to the previous installments.
 * The first two episodes of Rumbling Hearts seem like a sweet high school romance until the last two minutes when . The show then jumps ahead three years, advancing most of the leads into their post-high-school years and giving them new character designs. Also, the reguilar title sequence doesn't appear until episode 3. Oh, and it gets a lot less sweet.
 * Princess Tutu's 7th episode introduced the Dark Magical Girl, Princess Kraehe, and the 14th episode showed that the Happily Ever After isn't quite so happy.
 * Prétear revealed in episode 7 that.
 * Despite short lived, the 12 eps long Puella Magi Madoka Magica had heavy whams on the 1/4, 1/2 and 3/4 marks exactly.
 * Episode 3:
 * Episode 6:
 * Episode 9:

Live Action TV

 * Episode 7 of Buffy the Vampire Slayer is when we learn that Angel is a vampire.
 * The 3rd season of Twenty Four begins with a virus threat and a demand to release a drug lord from prison. By episode 7, it's revealed that the virus threat was all a hoax created by the good guys as part of a completed undercover mission to obtain the real virus.
 * Heroes second season. It takes until the 7th episode for all the plot threads to finally come together and make sense.
 * Chuck season 4. By the end of episode 7, we are introduced to the Big Bad and Chuck loses the intersect.
 * In episode 7 of Dollhouse, we find out that Caroline was investigating Rossum (the company that owns the Dollhouse) before she became Echo.
 * Episode 7 of the show Moonlight marked the reappearance of Mick's supposedly dead wife, as a human.
 * In season 3, episode 7 of Angel, Angel finds out that Darla is pregnant. In the 7th episode of the following season, the result of the aforementioned pregnancy and the show's lead female have sex. There's a reason that this is the example given on the Squick page.
 * Episode 7 of Fringe is the one in which we meet Mr. Jones, the first Big Bad.
 * Doctor Who: In series 6, the end of episode 6, and all of episode 7

Video Games

 * Fire Emblem: Path of Radiance : Chapter 7 is when the divided group comes back together, and when Greil Dies forcing Ike to go from rookie to commander of the Mercenaries at the beginning of Chapter 8.

Western Animation

 * Avatar: The Last Airbender : Episode 8, the second part of the two-part "Winter Solstice" episode. Part one focused on the nature of the Avatar, but it's part two where the series-long arc really starts. The series goes from 'Let's wander aimlessly, have fun, and maybe eventually get Katara to learn Waterbending,' to 'defeat Ozai in 8 months or the world gets destroyed.'
 * The Legend of Korra: Episode 6 and 7. Episode 6 has Amon and his Equalists perform a terrorist attack, blowing up the pro-bending arena, right after Amon de-bends one of the pro-bending teams and announces the beginning of the war between him plus his followers and benders. Episode 7 reveals that
 * Episode 8 goes a triple whammy.  Yeah.
 * South Park: "You're Getting Old".