What's behind the door?

James Spader Dishes On 'Blacklist' Twist & Turns, Teases Final Ending

It's the question all Blacklist fans are asking ahead of Monday night's episode, and the series' latest promo teases some serious answers (see video below).

Red (James Spader) may not want Lizzie (Megan Boone) to speak with his former wife, but the FBI profiler will manage to get her five minutes with Naomi Hyland (Mary-Louise Parker). While any relation of Red's will probably know at least something about Liz's past, it looks like Liz will get more answers from whoever/whatever is behind that locked door.

Liz & Ressler 'Have Chemistry' On 'The Blacklist', Megan Boone Talks Liz's Love Life

"Her life has been a mystery, but Liz's greatest secret lies just beyond the door," teased The Blacklist twitter.

Who could Liz have tucked away? Our first guess would be Tom, but that almost seems too easy. Hopefully the NBC drama will unveil the secret during "Dr. Linus Creel."

Meanwhile, Red will have yet another blacklister for the FBI to take down. Dr. Linus Creel pops up on the radar when Red suspects a social-psychological experiment is turning previously tame people into killers.

Find out more when The Blacklist airs Mondays at 10 p.m. ET on NBC.

Tags: The Blacklist television nbc