when does the flash show up in supergirl
Supergirl (TV series) On February 3, 2016, it was announced that Grant Gustin, who appears as Barry Allen / Flash on The Flash, would appear in the eighteenth episode of the first season, "Worlds Finest".[113] While no plot details on the episodes were released at the time, Ross A. Lincoln of Deadline.com noted that "the in-universe reason" for the crossover was due to Barry's ability to travel to various dimensions, thus implying that Supergirl exists on an alternate Earth to the Arrowverse in a multiverse.[114] The Flash episode "Welcome to Earth-2" confirmed this, showing an image of Benoist as Supergirl during a sequence where characters travel through that multiverse.[115] The earth that the series inhabits is Earth-38 in the Arrowverse multiverse,[116] and has been informally referred to as "Earth-CBS" by Marc Guggenheim, one of the creators of Arrow.[117]
The Flash (season 4) In July 2017, cast from the series appeared at San Diego Comic-Con International to promote the season, where exclusive footage was shown.[51] During the panel, a trailer for the season was shown, with James Whitbrook at io9 feeling that despite the "grim" tone, there was "some fun signs of the team coming together to protect the city without [Barry],... Sprinkle in a few wacky things, like, say a goddamn Samuroid ripped straight from the comics, and ladies and gents, you've got a good season of The Flash lined up."[52] Ben Pearson with /Film felt seeing Iris West deal with the absence of Barry was "a nice change of pace for that character", but anticipated that "Barry [would] be back two or three episodes in at the latest."[53] Collider.com's Allison Keene also noted Iris "getting an actual storyline" with Barry gone, and similarly presumed that he "[would] be back in the fold by the end of the first episode" alike to Flashpoint in the third season. She added, "There are some new foes, lots of action, plenty of tech — it’s great!"[54]