Alex reveals his tumultuous past with his father to his girlfriend Jo in Thursday's episode of Grey's Anatomy and fans will learn how deep their conflicts truly run. 

Cristina Yang is the attendee assigned to Alex's father, Jimmy, and Jo is her intern. The patient is post-operational following a valve replacement.

A preview video from the Oct. 17 episode, titled I Bet It Stung, reveals the origin of Alex's last name and viewers also see where he learned to be so suave with the ladies. Jimmy flirts with Jo and even winks at her from his hospital bed, all while unaware of the fact that she is dating his son.

Jo is then assigned to perform an echocardiogram on Jimmy, resulting in them spending more time together. Alex, on the other hand, refuses to even call him his father. Jo attempts to ease the tension by saying about her patient, "he's funny. You should talk to him; tell him who you are."

"Maybe he's changed. You've changed," she added.

Alex then confesses the real reason he will not bear to go near his hospitalized father, played by James Remar.

"The last time I saw his face I was punching him so hard I could've killed him," he tells her. "I'm just afraid I'll pick up where I left off."

ABC released the following synopsis for the new episode:

"Meredith jumps back into work but finds it hard to excel at both motherhood and being a surgeon. Stephanie tries to make a good impression on Jackson's mom, and Jo finds herself overly involved with her new patient. Meanwhile, Callie and Owen deal with an emotional situation regarding a patient."

Season 10 of Grey's Anatomy airs Thursdays on ABC at 9 p.m. ET.