Walter and Ralph's father figures will stir up trouble in Scorpion's "Father's Day."

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Walter's (Elyes Gabel) team will have escaped convicts to worry about this Monday, but the return of Ralph's (Riley B. Smith) absent dad and the re-ignition of Walter's negative feelings toward Agent Cabe Gallo (Robert Patrick) will make the case just that much more difficult.

"Next week's episode, titled Father's Day, will show us... flashbacks of young Walter offered a job from Cabe to create software to drop aids packages and how his trust was betrayed [when] the software was misused to drop...bombs," Spoiler TV revealed.

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O'Brien briefly touched on the aid package issue in the premiere, showing that he still struggled with the fact that his seemingly benevolent work went on to kill thousands of civilians, but he seemed to put it behind him when he chose to team up with Cabe.

The escaped convicts, however, will include a hacker who was forced to help his partners in crime steal millions over the Internet. This misuse of a genius' talent is sure to make Walter's blood boil.

Meanwhile, Brendan Hines will make his debut as Ralph's dad Drew, a character who will stick around for at least two episodes.

Find out more when Scorpion airs Mondays at 9 p.m. ET on CBS. Click the video below to see a preview for "Father's Day."