From prison guards to tattooed bikers, the NCIS: Los Angeles team will take on some interesting personas in "Rage."

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When a group of white supremacists get their hands on some stolen nuclear material, Sam (LL Cool J) and Callen (Chris O'Donnell) will resume their identities as prison guard and prisoner to take them down. Kensi (Daniela Ruah), meanwhile, will play a tatted-up biker chick that just so happens to be Callen's girlfriend.

The case will also drag up the past for one member of the team.

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"Great story. Callen, young & old, major interest &focus," executive producer John Peter Kousakis teased in February. "Watch for flashback in E618 Beginning of a significant relationship revealed."

As it turns out, this flashback will highlight the first meeting between Hetty (Linda Hunt) and Callen. The formidable leader of the Office of Special Projects has recruited several wayward orphans over the years and fans will finally get a chance to see the moment when Hetty became G's mother figure.

Find out more when "Rage" airs on April 13. Scroll through the photos above to get an advanced look.

NCIS: LA airs Mondays at 10 p.m. ET on CBS. Click the video below to see a preview for the series' next episode, "Blaze of Glory."