Warning: Major spoilers for On My Block season 3 are ahead.
Monse (Sierra Capri) and her dad had a good thing going on On My Block, but the truth about Monse's mother couldn't stay hidden forever. So in season 2, we finally met this mysterious figure, in Brentwood of all places. This reunion, however, did not end well in season 2 and it gets even worse in On My Block season 3. Every moment of it will stay with Monse forever.
To recap the moments that brought us here, to season 3: Monse's mom (Lisa Marcos) left when she was little, and her Dad was never too keen to find her. However, after a chance encounter in season 1, Monse tracks down her mother and ends up babysitting her half-siblings without deliberately revealing her identity. (Her mom figures it out pretty quickly.) In season 2, they meet face to face, acknowledge their relationship, and get to know one another.
During this get-to-know-you phase, we learn that Monse's mom is now Julia Whitman, after changing her name from Selena Finnie, and she's writing a "sort of" memoir about her past. Since leaving Monse and Monty (Reggie Austin), she left Los Angeles and moved back to finish this book. She has a white husband, two new kids, and an upper class lifestyle far from all the dangers in Freeridge — but also far from everyone Monse cares about. So, when Julia offers Monse a place to live, she's hesitant. Can she leave it all behind?
Unfortunately, Monse's decision is made for her when she learns that Julia has told her Brentwood friends, the mothers of the girls what would be Monse's new friends, that Monty abused her. Julia threw Monse's father under the bus so that the rich moms wouldn't think she was a bad person for abandoning her child, and that doesn't sit well with Monse. She's also suspicious that Julia is ashamed of having a young woman of color as her child. So Monse says goodbye.
This is why, in season 3, when Julia calls Monse, Monse continually ignores her calls. At a pivotal moment, Cesar's brother Spooky (Julio Macias) advises Monse not to let her mother back in. Contacting Monse is "for her," he says, "not for you. She just wants to clear her conscious. She disappears, comes back and expects you to welcome her with open arms? Now she wants to be a parent? Seems a hell of a lot easier when you don't have to actually raise a child. Screw that."
One episode later, Monse finds out her mom died by suicide. At the funeral, she speaks with her Australian psuedo-stepdad and discovers that Julia had run away and abandoned them more than once, and only came back in an effort not to repeat her past mistakes. There's so much about her that they didn't know, and tragically never will.
This moment, and everything that came before it is pivotal for Monse, who's on the precipice of potentially leaving Freeridge and changing her life forever. It undoubtedly gets her thinking about where her life should go, and by season's end, once the mystery is wrapped, she seems to find an answer.