The confines of the Bunker offer less opportunity for visual references but the script throws up several callback moments. After first emerging, John expresses surprise that Sam isn't in Palo Alto, the California city where the youngest Winchester was studying at the beginning of season 1. Later, when John has been given a full 16-year update, Dean tells his father that John's own Dad would be delighted to him finally in the Bunker. This is a reference to when time travel allowed Sam and Dean to meet their grandfather, Henry Winchester, who wished for his son to follow the family business and join the Men of Letters.
Predictably, the Winchesters bicker over their father's reappearance, with Dean wanting to enjoy the moment and Sam taking a more cautious approach - the same dynamic that has served Supernatural well since the very beginning. Sam also mentions remembering John lying on a hospital floor, a throwback to the season 2 premiere that saw Morgan's character sacrifice himself for Dean.
Dean also makes fun of Sam's intelligence by calling him an "egghead." In earlier seasons, it was common for him to mock his younger brother's bookish nature, but this petered out as the pair matured. It's quite telling that John's return brought out this more childish side of Dean's character once again. The boys soon return to town for dinner, only to find the flow of time starting to unravel. A "Mathesons Lumber and Home Center" sign can be seen in the background here, a nice nod to long-serving producer Craig Matheson, and while the location has changed from Little Rock to Lebanon, Dean's pouty "Wanted" poster mugshot is the same one used back in season 3.
Once the boys figure out that John's return has upset the balance of time, they find that Sam now sees Steve Jobs as a fashion icon and manages his own law firm - law being the subject he was studying at college in season 1. Dean, on the other hand, has dealt out a "lot of beheadings" - another self-aware reference to Supernatural's tendency for rolling heads.
Castiel And Zachariah
Meddling with the Supernatural timeline facilitates the return of evil Castiel and his contribution to this episode mirrors the very first appearance he made on the show, using the same "I'm an angel of the Lord" line, shorting out the lights and showing off his wings in an epic shot that directly copied that very first Castiel episode. It's also interesting to see Castiel going back to not understanding references to Earth culture when Zachariah compares him to Constantine - something that happened plenty of times in the angel's early episodes.
The restaurant setting of this scene is particularly apt, as Supernatural's angelic contingent have a history of scrapping in Earth's various dining establishments, and a psychic eye symbol can also be seen just outside of the restaurant's entrance. Zachariah goes on to note that it's hard for angels to fully sense the area of Lebanon, a phenomenon most likely caused by the angel warding surrounding the Winchesters' Bunker.
The returning Zachariah arguably steals this entire scene, and his mention of "big plans" for Sam and Dean is a callback to the season 4/5 arc where Heaven intended to use Dean as a permanent vessel for the archangel Michael to defeat Lucifer. Interestingly, it's Sam who kills Zachariah on this occasion, giving both brothers the honor of defeating the villain after Dean dealt the fatal blow for Zach's first death. Castiel is dealt with thanks to the return of the angel banishing sigil - a common tool in the Winchester arsenal before they decided that stabbing God's winged messengers with their own blades was much quicker.
Sending John Home
The climax of "Lebanon" largely focuses on the emotional impact of John's departure but still finds time to sneak in a few small Easter eggs. Season 11 villain The Darkness is mentioned and a Bob Seger song accompanies the Winchester family as they eat their final meal. Seger's music has played a pivotal role in Supernatural throughout the years and it's certainly an appropriate inclusion in this emotive scene.
With the timeline restored, the episode revisits the three teenagers Sam and Dean gave "the talk" to earlier in the episode and it's clear that they are in awe, one more so than the others perhaps, of the duo's fight against the supernatural nasties of the world. This plays into the ongoing recent theme of the Winchester brothers leaving a legacy behind them.
A real treat for veteran Supernatural viewers, "Lebanon" has plenty of details to explore on repeat viewings and delivered a hefty emotional punch with the return of John Winchester. There was perhaps one glaring omission in Adam, the son that John has apparently forgotten about completely, and it would've been fascinating to see how John might have reacted if Sam and Dean had mentioned that they not only found his secret lovechild, but stuffed an archangel inside him and locked him away in hell forever.
That aside, "Lebanon" will go down as a near-perfect love letter to all things Supernatural and with another season already confirmed, here's to the next 100.
Supernatural season 14 continues with "Ouroboros" March 7th on The CW.