When lifelong comic book fan Kevin Smith returns to the director's chair in the upcoming Supergirl episode "Damage," Katie McGrath's Lena Luthor will be forced to deal with the ramifications of her deployment of a lead bomb in the Season 2 finale to help rid National City of the invading Daxamites.

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According to the newly released synopsis for the Nov. 6 episode, Lena's seemingly heroic act may be the cause of some unwanted -- and possibly fatal -- side effects, as Morgan Edge tries to place the blame on the L-Corp CEO for a lead-poisoning epidemic affecting the children of the city. In an attempt to clear her friend's name, Supergirl will turn to National City's unwitting Kryptonian Samantha, aka Reign, but the battle could prove to be too much for even two Kryptonians to handle.

Here is The CW's official synopsis for "Damage":

When multiple children get sick from lead poisoning, Morgan Edge (guest star Adrian Pasdar) points the finger at Lena (Katie McGrath) and blames her creation of the lead bomb she made to save National City from the Daxamites. While Lena knows she never intended any harm, she fears there may have been a flaw in her design, leaving her responsible. Kara (Melissa Benoist) teams up with Samantha (Odette Annable) to clear Lena’s name, but it turns out to be harder than they thought. Meanwhile, Alex (Chyler Leigh) and Maggie (guest star Floriana Lima) make a crucial decision about the future of their relationship. Kevin Smith directed the episode written by Eric Carrasco & Cindy Lichtman (#305). Original airdate 11/6/2017.

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Airing on The CW Mondays at 8 p.m. ET/PT, Supergirl stars Melissa Benoist in the title role, David Harewood as Martian Manhunter, Mehcad Brooks as Jimmy Olsen, Chyler Leigh as Alex Danvers and Jeremy Jordan as Winn Schott, with appearances by Calista Flockhart as Cat Grant and Tyler Hoechlin as Superman.