"So Long and Goodnight" is the sixteenth episode of the sixth season of The Flash, and the one-hundred-thirtieth episode overall. It aired on April 21, 2020.
After Black Hole hires Rag Doll to kill Joe, Singh suggests he go into Witness Protection but Joe refuses to stop investigating Carver. While investigating Carver with Cisco, Ralph runs into Sue. Iris becomes suspicious of Eva.[src]
Originally set to air on March 31, 2020, it was pushed back to accommodate the halted production of every other TV show from the ongoing COVID-19 coronavirus pandemic.[1]
After being pushed to April 7, the episode was delayed yet again. Reruns of Crisis on Infinite Earths aired during that week instead.[2]
On March 30th, 2020, The CW released a graph of returning shows, confirming both The Flash and DC's Legends of Tomorrow would return on April 21 with new episodes.
On April 20th, one day before the release of the new episode, it was leaked online.
There is a mention of Prince during the episode that aired on the fourth anniversary of his death.
The title of this episode is a reference to the scene where Mirror Iris kicks Barry out of their apartment.
In one scene, the financial advisor asks Sue if she and Ralph are married, to which they both reply "gross". In the comics, the two of them are married.
Gallery
Videos
The Flash 6x16 Promo "So Long and Goodnight" (HD) Season 6 Episode 16 Promo
The Flash 6x16 Sneak Peek "So Long and Goodnight" (HD) Season 6 Episode 16 Sneak Peek