What happens in the opening scene of the play, Indiscretions?

Indiscretions opens on a scene of panic in Yvonne's chaotic bedroom. Yvonne, a diabetic, looks close to death. Her husband George thinks she has taken an overdose of insulin. Yvonne's sister Leo and George guess that Yvonne has been driven to desperation by the failure of Michael, the son of George and Yvonne, to return home the previous night. Yvonne explains that she forgot to eat or take sugar to balance her insulin dose as she was worried about Michael. Leo gives her sugar dissolved in water, and she recovers.