'Pretty Little Liars' Season 7 episode 15 spoilers: One of the PLL girls helps their enemy to protect her loved ones in 'In the Eye Abides the Heart' [WATCH VIDEO]

Troian Bellisario, cast of Pretty Little Liars or PLL (RTX21CHV) — Troian Bellisario (C) and the cast of Pretty Little Liars accept the award for favorite cable TV drama at the People's Choice Awards 2016 in Los Angeles, California January 6, 2016. Reuters/Mario Anzuoni

"Pretty Little Liars" (PLL), starring Troian Bellisario as Spencer Hastings, Lucy Hale as Aria Montgomery, Ashley Benson as Hanna Marin and Shay Mitchell as Emily Fields, will have an upcoming episode titled "In the Eye Abides the Heart," which airs on May 23 on FREEFORM. It will show one of the "PLL" girls crossing over to their enemy's side. Read on to learn more about this episode.

Spoiler alert: This article contains more 'Pretty Little Liars' spoilers. Read on if you want to know more about what happens in the upcoming episode.

"Pretty Little Liars" Season 7, episode 15 will show one of the girls supplying information to their enemy to protect her loved ones. It doesn't help that she's being blackmailed by A.D. Meanwhile, Emily will find supporting Alison (Sasha Pieterse) quite a challenge.

As for Aria, she'll give Ezra an ultimatum to fix his issues involving Nicole (Rebecca Breeds). Spencer will do everything in her power to have a meeting with Mary Drake (Andrea Parker). However, she will also encounter Wren (Julian Morris) along the way. Hanna will try to prove that Lucas (Brendan Robinson) is innocent but she will be surprised to learn something about him. She'll also be troubled with new information that she'll uncover. Detective Furey (Nicholas Gonzalez) will ask the "PLL" girls about Archer Dunhill. Plus, another person will know more about the secret of A.D.'s game. Check out the preview of this episode below.

'In the Eye Abides the Heart' guest stars

Troian Bellisario directed "In the Eye Abides the Heart," which was written by Joseph Dougherty. According to the Internet Movie Database (IMDb), David Bianchi (Bartender), Johnny Glasser (Bar Patron) and Lindsey Shaw (Paige McCullers) will be guest stars in this episode. The other members of the "Pretty Little Liars" cast such as Tyler Blackburn (Caleb) and Janel Parrish (Mona) will also appear in "In the Eye Abides the Heart."

'Pretty Little Liars' episodes

The episode before "In the Eye Abides the Heart" was "Power Play," which aired on May 9. It was directed by Roger Kumble and written by Lijah J. Barasz. It showed Ali remembering that Emily's donated eggs were implanted in her uterus while she was in the psychiatric hospital. Paige also decided to stay in Rosewood with Emily. As for Aria, she found out that Sydney (Chloe Bridges) is working for A.D. She offered Aria a chance to join the team.

The episodes after "In the Eye Abides the Heart" are "The Glove that Rocks the Cradle" (air date: May 30), "Driving Miss Crazy" (air date: June 6), "Choose or Lose" (air date: June 13), "Farewell, My Lovely" (air date: June 20) and "Till Death Do Us Part" (air date: June 27). "Pretty Little Liars" airs in Australia on Wednesdays at 8:30 pm on FOX8. It also airs in the US on Tuesdays at 8-9 pm EST on FREEFORM.