Barry is set to return to Earth-2 in "The Flash" season 2 episode 17.

"The Flash" season 2 episode 17 is entitled "Flash Back." According to TV Guide, Barry will become eager to go back to Earth-2 to halt Zoom in doing his evil plan; however, it seems that the villain is close to achieving his plans, so the scarlet speedster has to boost his speed.

As per the publication, Barry manages to go back to Earth-2 on time and dissimulates as his previous self to have his archnemesis Dr. Harrison mentors him how to run faster. At the same locale, Barry is also set to encounter his familiar enemy, Hartley Rathaway, and his old friend Eddie Thawne.

Along with his interest to gain more speed, a promo video also revealed that Zoom is Jay Garrick. Also, the clip showed that Iris has to move on from her past for her to walk the path to her future.

According to Carter Matt, episode 17 is set to be a huge episode, since it brings back some "old favorites" from previous episode, such as Thawne," whom fans will be seeing after his death, along with Harrison Wells in his Earth-1 form.

As per the publication, the episode is going to be both amusing and delicate, since Barry also had to learn something new without putting a conflict to his future. This means that he has to be more careful; otherwise, he may have a taste of what has happened to Garricks.

Fans saw Barry meet Kara in National City in "Supergirl's" crossover episode. This raises questions pertaining to whether the speedster unintentionally traveled back in time in an attempt to get from Kara's alternate world back to his own, according to Melty. Also, the publication mentioned that the inclusion of time warps and creatures in a distorted timeline resembles some "Doctor Who" features.

"The Flash" season 2, episode 17, "Flash Back," is set to air on Mar. 29.

Watch the episode's promo video here.