Although Monty died at the end of 13 Reasons Why Season 3, he was as much a part of the dark teen drama's final season as ever before. Clay, Ani, and the rest of the Liberty High kids who pinned Bryce's murder on Monty struggled to keep their dangerous secret during senior year, and the arrival of Monty's younger sister certainly did not help matters. Viewers may be wondering who Estela in 13 Reasons Why Season 4 is, and which side she could be on at the start of the series' final run, because she's kind of caught in the middle.
Spoiler alert: This post contains spoilers from Season 4 of 13 Reasons Why. Monty's sister was never mentioned in the series before, which makes sense because he always kept his home life private. But, she came into the picture at the beginning of Season 4, shortly after the death of her brother. Estela was clearly very conflicted about how to handle Monty's death — she had the whole football team coming to her with ways to pay respect to Monty, but she also knew Monty sexually assaulted Tyler, and she joined Jessica's anti-assault group Hands Off right off the bat.
Estela's storyline only became more complicated as she grew closer with Jessica while also realizing she may not know the full truth about what happened between Monty and Bryce. She confided in Ani that Monty killing Bryce did not make sense to her, because Monty considered Bryce to be like a brother, but Ani lied and said she had no idea why the murder could have happened.
Eventually, Winston introduced himself to Estela at the Find Your Drink party, and told her about his theory that someone in Clay's group of friends was hiding the truth about who killed Bryce. Winston then revealed to both Diego and Estela he found Bryce's final tape to Jessica in the school's photography lab. He then played it for them, and told them his (inaccurate) conclusion that Jessica had gotten Justin to kill Bryce and then the friend group framed Monty. Of course, both Estela and Diego had trouble believing this, since they'd both grown so close to Jessica, but it planted a seed of suspicion.
Still, Estela wan't all that much of an antagonist. During the active shooter drill in Episode 6, Estela was finally able to confront the hard truth about her brother. She found herself holed up in the bathroom with Tyler, and the two broke down talking about Monty. Estela and Alex Tyler bonded during the nightmarish experience, so much so that they ended up going to prom together.
In a season haunted by the ghost of Monty (both literally and metaphorically), Estela's story was a tough but important addition that constantly had viewers guessing.
If you or someone you know is seeking help for mental health concerns, visit the National Alliance on Mental Illness (NAMI) website, or call 1-800-950-NAMI(6264). For confidential treatment referrals, visit the Substance Abuse and Mental Health Services Administration (SAMHSA) website, or call the National Helpline at 1-800-662-HELP(4357). In an emergency, contact the National Suicide Prevention Lifeline at 1-800-273-TALK(8255) or call 911.