Summary

• Key episodes like the 'Pilot' & 'Devil's Trap' set the tone and narrative foundation of Supernatural.
• Introduction of pivotal characters like Castiel and Chuck change the series dynamics and pave the way for future storylines.
• Finales like 'Sacrifice', 'Alpha and Omega', 'Carry On' deliver powerful conclusions that define the essence of Supernatural.

Supernatural had 327 episodes by the time it wrapped its fifteenth season, with some exceptional episodes that defined the show. Supernatural began airing in 2005, and quickly built a dedicated fanbase. The series continued to be popular throughout its entire run, only coming to a halt in 2020 after fifteen seasons when the cast and crew decided to lay the show to rest.

However, in that time, Sam and Dean Winchester firmly established themselves as one of the most entertaining duos on TV. The series experienced plenty of changes throughout its lengthy run, but some episodes were pivotal to the overall narrative, while others served up equally fun monster of the week stories. While both were great, the episodes that changed the game are unmissable.

12 "Pilot"

Supernatural Season 1, Episode 1

Obviously, the first and most important episode to come out of the series is the "Pilot." The first episode perfectly sets up the events of the show, introducing the relationship between the brothers, and their willingness to put aside their differences and go take care of business. The show establishes its themes, tone, and all of the most important elements right at the top, setting up the series to be a huge hit.

The chemistry between Sam (Jared Padalecki) and Dean (Jensen Ackles) makes this episode, and indeed, the show what it is, and it's apparent from the start. While both brothers want different things out of life, they are willing to move mountains to each other and chase a common goal. The episode also features plenty of frightening moments and twists that help establish the series.

11 "Devil's Trap"

Supernatural Season 1, Episode 22

One of the best elements of the entire show is the outstanding finales and the cliffhangers between seasons. After Supernatural season 1 sees the boys embark on a hunt to track down their missing dad, the season 1 finale has them getting closer than ever. However, all is not as it seems, and the show ensures that viewers don't get too comfortable with their expectations before subverting the story.

This episode also introduces a key player in the Winchester team, their unofficial uncle, Bobby. Bobby is always at hand to offer advice when the boys' father is not in the picture, he is also very stern, and has a soft spot for the boys. The boys face off against the demon who killed their mother and Sam's girlfriend. However, when he possesses their father, things get messy. The episode then concludes with another twist and cliffhanger, setting expectations for how the rest of the series will go on.

10 "All Hell Breaks Loose" Part 1 & 2

Supernatural Season 2, Episodes 21 + 22

It may be cheating, but considering season 2 had a rare two-part ending, it's worth including Part 1 and Part 2 as a single story. The boys came face to face with Azazel, the yellow-eyed demon once again, but this time, he came prepared with some champions of his own. Throughout the season, Sam has been distant with his brother as he learns about the demon blood in his system and the powers that they afford him. However, when pitted against other initiates, Sam is caught off guard and killed.

Part 2 then builds on this narrative with Dean making a deal to trade his life for Sam's, a single year before the debt is to be collected. This is the first of many times throughout the show that the boys make back-door deals to stay out of the afterlife, which makes it one of the most important of the show. This episode also concludes the narrative with Azazel and John Winchester, allowing the series to move into a new stage of life.

9 "Lazarus Rising"

Supernatural Season 4, Episode 1

Jumping ahead a few seasons, the next key episode is at the start of season 4, when another character s the fray. Castiel makes his debut in this episode of Supernatural, and despite his lack of social awareness, he quickly establishes himself as a fan favorite character. In fact, Cas is so important to the rest of the show, that he remains a core member of team Winchester to the final season, often aiding on missions and providing some celestial backup.

However, the episode is also important because it changes the dynamics from a show about demons and monsters to one that includes heaven, angels and God himself. The series is never the same after this point, and though it takes time to find a new groove, this opens so many doors for the future of the series. Easily one of the most important episodes of the entire show.

8 "The Monster at the End of this Book"

Supernatural Season 4, Episode 18

Carrying on from the God theme, later in season 4 another very important character is unveiled. However, his true identity remains hidden for several more seasons. Despite this, Chuck Shurley makes an impression right from the off as he comes face to face with the real life characters from the Supernatural book series he writes.

This show kicks off a trend for meta episodes that comes back on several occasions, but it's also important because of Chuck. Initially, the boys and Cas believe Chuck to be a prophet, who is capable of seeing the future and recording his visions. Thus, the series of novels which closely depicts the lives of the Winchester boys and ther hunts. But Chuck is in fact God. Having grown tired of his life in heaven, he decided to jump onto the planet and experience his work for himself.

7 "Sympathy For The Devil"

Supernatural Season 5, Episode 1

After the close of season 4, a shock reveal had the brothers come face to face with Lucifer himself. But his story truly begins in season 5, in particular the opening episodes where the boys have more interaction with the king of Hell. The fallen angel is a pivotal part of the show from here to the very end, and his relationship with the Winchesters is just beginning in season 5.

Lucifer spent millennia caged, and now, with his newfound freedom, he sets out to raise a little Hell on Earth. However, the boys are there to stop him and cause the devil great inconvenience. This is another turning point for the boys as they graduate from fighting run-of-the-mill demons to literal archangels who wield the power of gods. Not to mention, Mark Pellegrino does a fantastic job in the role and is a welcome addition to the show.

6 "Sacrifice"

Supernatural Season 8, Episode 23

Another finale, this time from season 8, when the boys are setting out to complete a series of trials to shut the gates of Hell forever. However, the trials are anything but simple, and they need to use a variety of methods and friends in order to get their best shot. Dean is handcuffed to the demon, Crowley, whom he attempts to make human again through injections of his own blood. The boys turn to Kevin Tran, a new prophet, and Cas fights his own kind to get answers.

However, the episode layers together several complex threads to make one exciting story. The characters have become so familiar and well-developed that the emotion has multiple hard-hitting emotional moments, and the final moments are spectacular. As the episode comes to a close, hundreds of angels fall from the sky, leaving audiences with yet another spectacular Supernatural season finale.

5 "The Prisoner"

Supernatural Season 10, Episode 22

The penultimate episode of season 10 also comes in as one of the most defining episodes of the show. The beloved character Charlie Bradbury died in the previous episode, and Crowley and Rowena's pre-existing relationship is expanded on. In addition, it sees Dean fight against the Mark of Cain which is controlling him to almost break out of his heroic nature and kill a human.

Despite the show having already been running for a decade, this episode shows that the creativity and talents of the writers are still pushing out incredible new stories and relationships. Life changes pretty fast for a hunter, but with the talents involved here, every single second of it is worth watching. But if it had to be boiled down to the bare bones of the series, this episode deserves a spot.

4 "Alpha And Omega"

Supernatural Season 11, Episode 23

While this episode may not be one of the best finales in the show's history, it's pivotal for several different reasons. Sam and Dean team up with God in an effort to take down his sister Amara. However, when Dean comes face to face with Amara, he is able to talk her down from her vengeful position. Dean relates with her about family being the most important thing, and she takes this on board.

Rather than end the universe, Amara heals her injured brother, and the two go out into the void to explore and create new worlds, leaving this one behind. The episode also features the return of Mary Winchester, who is resurrected out of gratitude from Amara for repairing her and her brothers' relationship. Finally, it is also a pivotal moment when the London chapter of the Men of Letters reveal themselves to the boys, which sets up several stories in the coming seasons.

3 "All Along The Watchtower"

Supernatural Season 12, Episode 23

The following season ends with a similarly pivotal finale, despite not being the most engaging. Characters who were long gone return, and the boys discover the Apocalypse World, where angels and demons fight to the death, and lay waste to the Earth beneath them. This world is largely the same as that of the boys, except for the main difference being that they were never born.

The truth is, the Winchester's have saved the world and universe more times than people can count. When they are out of the picture, hell breaks lose, angels engage in civil war, and the feelings of these devastating moments are felt far and wide. Certainly a huge moment for the state of the events in the final season, but also important for finding a way to bring back some of the best, most beloved characters there.