Alceste hates people of all races, creeds, sizes, and languages. They aren't sincere enough for his liking, so as far as he is concerned, all of humanity can go jump in a kite or fly a lake, or whatever.
Everyone except for his lovely Célimène. Even though she is the queen of insincerity, Alceste loves her. Add in a love triangle between Philinte (Alceste's BFF) and Éliante (who has a crush on Alceste), and a lawsuit, and we have the basis of our play. Sounds like a pretty tangled web of intrigue.
We get the idea that Célimène has waayyyy more than one guy on the side. And it's not just us. Actually, everyone is talking about it. Alceste is getting more and more jealous and paranoid about this. But every time he tries to straighten out his suspicions, he gets pulled into some lawsuit or argument. Things are heating up.
Alceste lost his lawsuit and is on the lam! Célimène is cheating on all her boyfriends! They find a letter in which she insults all of them! It's not possible to have more drama! We use exclamation marks excessively!
One by one, Célimène's boy toys insult her and leave. Alceste is the only one left behind, but she refuses to run away with him and become Mrs. Hermit. Since Alceste still doesn't love Éliante, she and Philinte get together.
Alceste runs off to be a hermit all alone. Philinte and Éliante chase after him, probably to have more zany adventures.