Furious just revealed the meaning of the memory box and the killers motive

Furious has introduced Catherine (Lola Petticrew) through her kills and the manipulative strategies she's undertaken to achieve them. But in episode 4 of Elizabeth Meriwether's new crime drama, FBI agent Alice Black (Emmy Rossum) uncovers the past of this mysterious killer, including her name, the meaning of her memory box, and her motive.

In "Flash Flood," a trip to a group home for children reveals the that Catherine was besotted with Isabel, who died under mysterious circumstances years ago. Catherine is on a murder-fueled quest to find out what happened, and make anyone involved with Isabel's death pay.

In an interview with Petticrew, they said of Catherine's relationship with Isabel, "She's absolutely head over heels in love with Isabel. I mean, that's her total motivation... She was totally and utterly in love with her, and she was her best friend."

Petticrew also spoke to the meaning of the memory box, which a social worker tells Alice was encouraged to give the foster kids hope for their futures.

"That box of memories and those couple of bags are all that she has," Petticrew said. "She has difficulty remembering a lot of things, and so I think it's her attempt to try to map things out, in a way. And she's a magpie; she's attracted to shiny things. That's just kind of who she is. She likes the garish and the big."

They also reflected on the dance scene, where Catherine dances in Alden's mother's bedroom to Rihanna's "We Found Love."

"When she dances to that Rihanna song, for me, that felt like," Pettigrew mused, "she was constantly forced from being a child to use her body in a way that is for the eyes of men. And in the performance of that dance, I wanted it to be animalistic in the sense that this is her moving her body in the way that she wants it to move, in the way that she feels comfortable with. It is an exercise to let go and feel like herself. And so that sequence was actually really important."

Furious is now streaming on Hulu, with a new episode each Monday.