'The Magicians' Season 5 Episode 9 shows how Plum's time-traveling ability can be used against Rupert Chatwin
Plum could use a memento from Fillory's timeline to bring the gang back to the time just before Rupert woke up. The gang could then use some collective magic to make sure that Rupert would keep slumbering
In a hectic episode for 'The Magicians', with the big Rupert "Sebastian" Chatwin (Sean Maguire) reveal, we also see the return of Plum Merritt Chatwin (Riann Steele) after she "traveled", disappearing before the gang's eyes in episode 4, after she plucked off the protective patch from her neck.
In Lev Grossman's books, Plum was Rupert's great-granddaughter. So her return in the same episode that reveals the Dark King's origins means that the TV show will also build on this connection. We also discover that she is an accidental time traveler, dragging Penny with her to 1998 and then the 1920s where everyone, including Brakebill's professors and students, were "casually racist".
Unlike other Travellers, who can travel to other spaces, Plum can travel to different times if she holds a memento from that day in time. This realization was a bit horrifying in the episode when Penny Adiyodi (Arjun Gupta) and Plum search through their pockets for mementos of the day they traveled from but only find objects that will let them travel forward to 2009 at the most, instead of 2020.
It is only when Penny realizes that since he broke Quentin's plaque on the day that they traveled from, the engraving was a "new object" and a memento of that day in time. Plum's time-traveling abilities could tie into how the gang tackle Rupert.
Fen and Margo found out from Christopher Plover (Charles Shaughnessy) that Rupert woke up because of the powerful magic surges and became Fillory's Dark King, desperate to bring back his love, Lance. So technically, Plum could use a memento from Fillory's timeline to bring the gang back to the time just before Rupert woke up.
The gang could then use some collective magic to make sure that Rupert would keep slumbering. Ergo, there would be no problem with the Takers, and Fillory would be safe and dictator-less once again. However, if this plan fails, they would have to find a way to kill Rupert in his sleep.
For now, we also know that Rupert cannot be killed unless Fillory is destroyed because of "conduit" magic that ties Rupert's life to Fillory's existence. This makes the handy World Seed an important object since it can be used to create a new world to resettle Fillory's denizens. But with Alice Quinn (Olivia Dudley) and Kady Orloff-Diaz (Jade Tailor) being kept hostage by George ( Geoffrey Arend), it is a tricky and dangerous situation.
George is not kidding around, cutting off four of Alice's fingers, and mounting an elaborate illusion to trick her into giving him the instruction page on how to grow the World Seed. Alice and Kady will be lucky to get out alive and the page is the only bargaining chip they have. But we can expect their story arc to tie into the Fillory storyline in the next few episodes.
It is still not certain where the "Signal" story arc is going. Both Penny and Plum were transported to the mysterious room that they had gone to before, which Plum remembered vaguely after coming back. The room is filled with antiques and despite Plum trying her hardest, she seemed unable to teleport herself and Penny out of it. So while this episode does clear some things up, it has left even bigger mysteries in its wake that will have to be resolved by the time the season finale airs.
'The Magicians' airs on Wednesdays on Syfy at 10/9c.