Supernatural celebrated 300 episodes with "Lebanon," a treat for long-time fans of the series. Thanks to an ancient Chinese pearl, which granted whoever held it whatever their heart desired, the Winchesters were reunited... well, almost all of them (sorry, Adam). John Winchester was plucked out of time from back when Sam was still at Stanford, John and Dean were hunting (separately), and Mary was dead.
The family reunion couldn't last because it changed the timeline and who Sam and Dean became. However, while it did, fans were treated to plenty of easter eggs, memorable moments and even another long-dead character return.
Sam and Dean are known as the Campbell Brothers around Lebanon, Kansas. Some of its residents also aren't quite sure what to make of them and what they sometimes have in their car. They have used many, many aliases over the years during hunts, often with fake law enforcement badges, but this is different.
Their use of Campbell is a nice nod to their family's past. Their mother Mary Winchester's maiden name was Mary Campbell, and Supernatural has introduced several members of the Campbells, a family of hunters, over the years.
When Dean held the pearl and expected to get his heart's desire — Michael out of his head — the lights in the bunker went out. The brothers were then attacked by a mysterious figure, and the three fought in the dark. When the lights came on, they realized it was their father, John.
That called back to Dean's introduction in the pilot. Sam heard a noise in his apartment and fought an intruder in the dark. That intruder was his brother, and it was the first time viewers saw the Winchesters together as adults.
When Dean first went to Sam in the pilot, Sam insisted he had to be back for a law school interview. When John first showed up, he expected Sam to be in Palo Alto because he thought it was 2003. Because they pulled John out of the timeline, their lives began to change.
In this alternate timeline, Sam ran a law firm and loved kale, a nod to his healthy eating habits. While Dean was still hunting, Sam wasn't, and family wasn't as important to Sam as it was.
In the new alternate timeline created by Sam and Dean plucking John out of 2003 and bringing him to the present, the angel Castiel wasn't their friend. Instead, he worked with Zachariah, and they showed up in Lebanon to figure out who was messing with time. Castiel acted as Zachariah's muscle when they questioned those in a restaurant. The way Castiel introduced himself to them was reminiscent of his introduction back in Season 4.
"My name is Castiel," he said. "I'm an angel of the Lord." Lights burst, and he showed off his wings. That was pretty much what happened when Dean first met Castiel: the lights, the wings, and even the words. "I'm an angel of the Lord," he said.
In the 300th episode, John remembered his and Sam's fight before Sam left for Stanford. However, for Sam, that fight was a "lifetime ago." He explained to John that what he remembered was his father, lying dead on the hospital floor.
Sam was the one to find John in the Season 2 premiere. When he did, he dropped the coffee cup in his hand, and it landed perfectly on the floor. Coffee splashed everywhere as he ran to check on his father. He was too late, and the episode ended with the Winchesters losing their father.
Jeffrey Dean Morgan as John Winchester wasn't the only familiar face to return in the 300th episode. Kurt Fuller returned as the angel Zachariah, thanks to Sam and Dean changing the timeline by bringing their father from 2003 to the present. Just like the first time, he was a problem for the Winchesters.
Zachariah didn't survive the milestone hour, and this wasn't the first milestone episode that featured his death. The angel was also killed in the series' 100th episode. The first time, Dean did the deed. This time, it was Sam.
As Sam and Dean realize they've changed the timeline, angels Zachariah and Castiel arrived in Lebanon, Kansas. "Come on, Constantine," Zachariah said to Castiel. The other angel didn't understand that reference, a nod to when Castiel knew nothing about pop culture and to his familiar look.
Castiel's trench coat, white shirt and tie is familiar to fans of the DC Comics series Hellblazer. Constantine wears a similar look, and CW fans can now see Matt Ryan sporting it over on DC's Legends of Tomorrow.
Anyone who has watched Supernatural knows how important the Impala (Baby) is to the Winchesters. The car originally belonged to John, thanks to a little advice from Dean during a trip to the past. The 300th episode remembers that, ending with John back in 2003 and waking up in the Impala.
However, since then, Baby has become Dean's car — and he doesn't take it too well if anyone touches her. In the 300th episode, a teenager stole her, and as soon as they found her, he immediately checked on her, a nod to his reunion with his car in the Season 2 episode, "Simon Said."
For the past several years, Sam and Dean traded in a life on the road, living from motel to motel, to living in the Men of Letters bunker. As they explained to John in the 300th episode, his father, Henry, helped them find the bunker, making them Legacies because of the Winchester name.
John thought Henry had abandoned him as a child, but Henry really traveled through time to the year 2013. While he, Sam and Dean dealt with the demon Abaddon, Henry died. He never returned to his time.
By bringing John to the present from 2003, the timeline changed for the Winchesters. Sam was running a law firm, but Dean's life wasn't actually much different from what it's been all these years. He was still hunting, and there was a "Wanted" poster for him. He was wanted for assault, murder, and credit card fraud. Dean's mug shot should have been familiar to long-time fans.
It matched his mug shot from the Season 2 episode "Folsom Prison Blues." He and Sam got themselves arrested to investigate a case inside a prison.