Liz (Megan Boone, left) is keeping a secret from Red (James Spader, right) in Season 2, episode 5 of "The Blacklist." NBC

Red (James Spader) and Liz (Megan Boone) have spent the last two episodes (episode 3 and 4) of NBC’s “The Blacklist” hunting down corrupt doctors, but it looks like in episode 5, titled “The Front,” they might just be in need of one. The synopsis for the next episode reveals the next person on Red’s list is an eco-terrorist trying to use a disease as a deadly weapon.

The promo for the new episode makes it clear the new villain will be attempting to commit an act of biological terrorism after obtaining samples of pneumonic plague. It will be up to Red and Liz to stop him. However, a picture from the new episode, shown above, show’s Liz in a hospital bed. Will she be infected?

On top of that, the synopsis also reveals Liz will try to shake the man Red has had following her for most of the season so far. Though fans have not yet met the man, they have seen him tracking her and most recently saving her from Dr. Linus Creel (David Costabile) in episode 4. However, it was revealed at the end of episode 4 Liz is hiding a big secret from Red, and though fans do not yet know what it is, Liz does not want to Red to find out.

Watch the promo for episode 5, “The Front,” below:

Will Red figure out Liz’s secret in the next episode? And how will the two of them stop the eco-terrorist? Plus, who is the girl Red is desperate to find that he alluded to in the promo? Fans will have to wait until next week to find out. “The Blacklist” airs on Mondays at 10 p.m. EDT on NBC.

What is Liz’s big secret? Tweet your thoughts to @Ja9GarofaloTV.