An ex-team Scorpion member kidnaps Toby and threatens his life in the upcoming finale episode, titled "Toby or Not Toby," of the second season of the action drama "Scorpion."

Team Scorpion has to come up with a clever plan that has to outthink their unstable ex-team member Mark Collins who kidnaps Toby. He also threatens to kill Toby if the team does not give in to his cunning demands.

The promo trailer for "Toby or Not Toby" shows the battle between one mad genius and the team of geniuses. Sylvester realizes that Mark became crazier than ever. Walter has a hunch that rescuing Toby would not turn out good. Mark gives Toby the chance to call Happy on the phone. Toby tells her how much he loves her. Mark reminds Toby that he is going to die on that day.

In other related news, executive producer Nicholas Wootton revealed a little bit about Walter in the upcoming season 3. At the 2015 WonderCon, Wootton said, "Walter moves at his own pace and his pace is extremely slow. We see that he has these aspirations and in order to know what you're missing you have to see it threatened. We're showing Walter what he could lose." Fans can also expect a huge development in Paige and Walter's relationship.

Megan's death will also easily be forgotten by the team, especially Sylvester. Ari Stidham, who plays as Sylvester, explained, "She taught him how to get over her. The whole point was to be with somebody, to share this love and to lift each other up as long as we can until the shoe drops."

Meanwhile, the previous episode, titled "Chernobyl Intentions," saw the team in Chernobyl to repair a decaying nuclear reactor before another tragedy happens. Sylvester and Paige ended up trapped inside.

"Scorpion" season 2 finale will air next Monday, Apr. 25, at 9 p.m. on CBS.