"The Flash" Season 3 says a lot on Barry losing his memory. He will be traveling back in time to correct some mistakes done in the past, but while traveling, there is a great possibility he may lose his memory and forget his way home.
Barry Allen played by Grant Gustin is now living a normal life as he always dreamt of. He will be dating Iris West played by Candice Patton. Also, a new kid Flash played by Keiynan Lonsdale who had the same powers like him is now in charge with the city while "The Flash" is not yet back in norm.
According to Movie News Guide, while Barry is living happily with his parents as they were still alive. He also forgot the consequences on the decisions he made and it would affect the scenes of "The Flash" Season 3.
In "The Flash" Season 3, Barry forgot every recent memories and replaced it with his childhood ones. The memories while he was still on his juniors and college days. It appears that playing with time will have grave consequences for him.
As per Screen Crush, new casts will be joining such as the likes of Grey Damon who will play as Mirror Master, Ashley Rickards as The Top and Joey King as Magenta. Also, Dr. Alchemy will be voiced by Tobin Bell and Harry Potter star Tom Felton has also signed to be a regular cast.
"The Flash" Season 3 will return on the small screens on October 3. As for the entire storyline, that remains unsettled and unknown.