In Grand Theft Auto V, you play as three criminals (Franklin, Trevor and Michael) who rob banks in a series of heists to guarantee their retirement. The player can switch between the three characters, at any time, to see what they're up to in their personal lives.
The core aspects of gameplay in this game are driving cars are engaging shoot-outs with people who oppose these criminals and car chases at high speeds to escape cops and other people. Almost all of the characters in this game are heartless and sociopathic, as this game is an extreme satire on the flaws of modern America.
But there is more than just violence here. You can scuba dive, play tennis, play golf, and much more. There is a giant open world with large cities, the wilderness, beaches, forests and the countryside. The game is at it's best when you aren't in your criminal pursuits, but instead just driving a motorcycle in the sunny city (based on Los Angelos) listening to your favorite radio station, or riding a quad bike up mountains and gliding off via parachute.
There's not much educational or moral value to be found here, but it's immensely entertaining. Keep in mind that there are a lot of aspects of this game people will find disturbing, such as a part of the game where the player must violently torture someone in order to progress.
Between it's graphic violence, liberal use of profanity, and crude misogynistic humor, it's by no means suited for kids, but adults may have a fun time with this game if they don't have moral reservations against it.