"Arrow" season 8 episode 7 happens to be the midseason finale and the last episode before the epic Arrowverse crossover "Crisis on Infinite Earths" kicks off on Sunday, December 8. In this episode, Oliver Queen and his team go back to a familiar place which will bring back some old memories and old nemesis. Here is everything we know so far about the next chapter of the final season of "Arrow."

[Spoiler alert! This article contains spoilers for "Arrow" season 8 episode 7. Steer away immediately, if you don't want to learn more about it.]

As we move into the finale, Green Arrow continues his emotional journey where he faces his personal demons and the demons of the outer world such as The Monitor. The next step in his journey to find the truth about Mar Novu, also known as the Monitor, takes him to a familiar place called "Lian Yu."

Lian Yu, which also means "Purgatory," holds an important place in Oliver's life as he spent five years stranded on this island that is located in the North China sea. At the same place, he lost several important people in his life after Adrian Chase set up multiple explosions during a crusade against Oliver. As he returns to this place, it is expected to bring back dark memories for Oliver who has faced an emotional ordeal recently.

Arrow season 4 finale
Stephen Amell as Oliver Queen/Arrow in The CW show The CW

"Arrow" season 8 episode 7 is aptly titled "Purgatory" and it will see what happens when Oliver goes back to Lian Yu. Here, invested in his new mission, Oliver meets an old friend who will be assisting him in the looming Crisis. This old friend happens to be Yao Fei as played by Byron Mann. He was the hooded hero's friend and mentor when he was at Lian Yu and protected him from the enemies. As Team Arrow reunites, they will also be dealing with an old enemy.

"Arrow" season 8 episode 7 airs Tuesday, December 3 on The CW.