The Flash: Season Zero

The Flash: Season Zero, also known as The Flash: Zero Year, is a comic book series set between the first season The Flash episodes,  It launched on September 8, 2014, and will release every fortnight. The first printed collection of the comics was released on October 1, 2014.

The series is co-written by Brooke Eikmeier and Katherine Walczak with art by Phil Hester and Eric Gapstur. The series has a lighter, more fantastical feel than the show, including outlandish and "costume-y" characters.

A group of circus performers will feature as villains, led by Mr. Bliss. Due to the S.T.A.R. Labs particle accelerator explosion, the rogues will all have superpowers, Mr. Bliss himself having the ability to manipulate a person's emotions. Having felt too pushed around, they will decide to take it out on society.

Synopsis
An all-new digital first series From the world of the highly anticipated new TV show The Flash! Follow the adventures of Barry Allen as he struggles to balance his job as a police crime scene investigator, his unrequited crush on Iris West (who also happens to be his boss' daughter) and his new life as Central City's guardian angel! Don't miss out!

Freak Show (After: '"'Things You Can't Outrun'",'   'Before' :  '"'Going Rogue")

 * "The Strongman Cometh" (September 8, 2014)
 * "Who Let the Chimps Out?" (September 22, 2014)
 * "A Goodnight Hiss" (October 6, 2014)
 * "Big Top Brawl" (October 20, 2014)
 * "The Talented Mr. Bliss" (November 3, 2014)
 * "A Captive Audience" (November 17, 2014)
 * "Showtime" (December 1, 2014)
 * "The Big Finale" (December 15, 2014)

Smoak Signals '(After: '"'Going Rogue'")

 * Part 1 (December 29, 2014)
 * Part 2 (January 12, 2015)

Continuity
Though it was initially announced that the comics would take place between episodes 1 and 2, chapter 8 clearly shows the prison beneath S.T.A.R. Labs, established in episode 3, and the epilogue shows Barry fighting Captain Cold. As there are no substantial narrative gaps in the comics, the "Freak Show" section can be assumed to take place between the events of "Things You Can't Outrun" and "Going Rogue". Given the dialog between Barry and Felicity in "Smoak Signals", it can be assumed the section takes place after "Going Rogue".