Cléante Timeline and Summary

Alone with his sister Élise, Cléante reveals that he is in love with a girl named Mariane and is determined to pursue her no matter what his father says.
In the very next scene, Harpagon informs Cléante that he plans on marrying Mariane. Cléante, of course, is not a fan of this plan.
Cléante, with no money of his own, arranges for a loan so he can help out Mariane and her mother financially. It turns out, though, that the lender is Harpagon himself. Cléante and Harpagon have a big argument about who is worse, the person who spends too much or the person who preys on people's desperation by loaning money at high interest.
When Mariane visits the house, Cléante kisses her hand and tells her (in code) that he wishes she weren't marrying his dad. To make his dad angry, he also slips a ring off of Harpagon's finger and gives it to Mariane as a gift from the old man.
Harpagon soon tricks Cléante into revealing his affection for Mariane. Cléante vows that he will never give up pursuing the girl and that there's no way she'll marry Harpagon.
When he finds out that his friend La Flèche has stolen Harpagon's cash box, Cléante uses the money to blackmail Harpagon into giving up Mariane.
Eventually Anselme reveals his identity as Mariane's father and ensures that she will marry Cléante. The two get engaged.