"Gotham's" season finale is fast approaching and it is revealed that Fish Mooney is set to return to the titular city in season 2 episode 21.

"Gotham" season 2 episode 21 is entitled "A Legion of Horribles." According to Spoilers Guide, Dr. Hugo Strange is set to welcome back a familiar being to Gotham City, following his revival of Fish Mooney in Indian Hill. More details on who this person really is, his or her purpose, and the impact of his or her return to Gotham and the people in it are yet to be revealed.

Along with the familiar face, Bruce is also set to learn that his friend is in danger. As a result, the former decides to enlist Gordon, Lucious, and Alfred's help and works hand in hand with them. Whether they are going to be successful in saving Bruce's friend or not is yet to to unveiled.

Strange is known to have several experiments in the previous episodes and it is viewed that such scientific endeavors are dedicated to his evil plans. According to Spoilers Guide, more of his experiments are bound to be unveiled in "A Legion of Horribles."

Fans are set to have some bird's eye view on Strange's plans in "Gotham" season 2 episode 22, the season finale. Entitled "Transference," Gordon, Bruce, and Lucius opted to stay at Indian Hill while Gotham City is set to face a new threat, according to Spoilers Guide. As per the publication, the episode will also see Strange's inmates try to plot their escape and begin their new lives.

"Gotham" season 2 episode 21, "A Legion of Horribles," airs on May 16 while episode 22, "Transference" (season finale) is set to air on May 23.