Here is the story summary for that episode:
While Mary and George are away, Meemaw (Connie) babysits Missy and Georgie. Missy takes advantage of the lack of parental supervision, leading to mischief. young sheldon s05e21 720p web h264
Sheldon and Dr. Sturgis take a road trip to the Texas coast for a geology conference. Sheldon is very excited about the academic aspect, but Dr. Sturgis tries to teach him about "romance" and social cues when they encounter a girl Sheldon's age. Sheldon's attempt to apply logic to dating fails spectacularly. Here is the story summary for that episode:
Based on the release title you provided ( "young sheldon s05e21 720p web h264" ), that corresponds to of Young Sheldon , titled: Sturgis take a road trip to the Texas
The episode highlights the growing distance between George and Mary, while Sheldon remains oblivious to the family turmoil, focused entirely on his own interests.