'The Blacklist' Season 4 episode 20 spoilers: A mercenary targets Liz in 'The Debt Collector' [VIDEO]

“The Blacklist” cast RTX121XB — Cast members (front L-R) Diego Klattenhoff, James Spader, Megan Boone and (rear L-R) Ryan Eggold and Harry Lennix participate in a panel for "The Blacklist" during the NBC sessions at the Television Critics Association summer press tour in Beverly Hills, California July 27, 2013. REUTERS/Phil McCarten

"The Blacklist," starring Megan Boone as Elizabeth Keen, Hisham Tawfiq as Dembe Zuma and James Spader as Raymond "Red" Reddington, will have an upcoming episode titled "The Debt Collector." It will be about a mercenary that targets Liz. Read on for the latest "The Blacklist" episode guide.

Spoiler alert! This article contains 'The Blacklist' spoilers. Read on if you would like to know what happens before the new episode airs.

According to a press release from NBC, "The Blacklist" Season 4, episode 20 will feature a dangerous mercenary that will target Liz. This forces Red to pull out all the stops and ask for help from an unlikely source. Elsewhere, Ressler (Diego Klattenhoff) will experience some hitches as he tries to be ahead of Agent Gale's (Enrique Murciano) investigation.

'The Debt Collector' guest stars and the rest of 'The Blacklist' cast

The Internet Movie Database (IMDb) lists the guest stars of this episode as Daniel Covin (Tyler Obermeir), Barrett Martin (Agent), Lindsay Mushett (Lisa Parker), Porter Kelly (Forensic Tech) and John Trejo (Ricardo). Fisher Stevens will also appear in this episode along with the rest of "The Blacklist" cast such as Mozhan Marnò (Samar Navabi) and Harry Lennix (Harold Cooper).

'The Blacklist' 2017 episodes: 'Dr Bogdan Krilov,' 'Mr Kaplan' and 'Mr Kaplan: Conclusion'

The 20th episode of the NBC drama's Season 4 follows the episode titled "Dr Bogdan Krilov," which airs in the US on May 4. It will feature a Blacklister that can manipulate memories. This will make Liz doubt her own experiences. Ressler will also receive a lead connected to Justice Department official Reven Wright's disappearance. Plus, Gale will work double time on his investigation.

A sneak peek video was posted on the show's official YouTube channel. It features scenes that suggest how far Kaplan (Susan Blommaert) is willing to go for her vengeance against Red. Unfortunately, Liz and her family, including her baby, will not be safe. "Kaplan has told the authorities about the bodies," Liz says in the video. "It seems Kate has started her endgame," Red confirms. Apparently, no one is safe anymore.

"The Debt Collector" airs in the US on May 11. The episodes after it are "Mr. Kaplan" and "Mr. Kaplan: Conclusion." It will both be aired on NBC on May 18.

"The Blacklist" TV series airs in Australia on Thursdays from 11:30-12:30 am on 7flix and on Channel 7 every Sunday from 10:30-11:30 pm. In the US, it is aired on NBC from 10-11 pm ET/PT.