We're back in the garden room. All the doors stand open and the lamp is still on the table. There's a faint, fiery glow coming through the windows. Mrs. Alving and Regina are looking at the remains of the Orphanage.
Mrs. Alving goes out to look for Oswald, and just then Pastor Manders comes in, in a paranoid tizzy.
Engstrand comes in hot on Manders' heels, implying that the prayer service is what caused the fire – and therefore Manders is responsible. In fact, Manders is the person who basically lit a match to the whole place.
The Pastor is sweating. Engstrand kindly reminds him that the papers won't handle him too gently.
Mrs. Alving comes in without Oswald – he's still at the fire. She seems relieved that the orphanage burned down. It wouldn't have done anyone any good.
Mrs. Alving asks if the Pastor will take all the papers with him? She doesn't want to hear anymore about it. He can decide what to do with the money that would have kept up the orphanage.
Engstrand pipes up: think of the Sailor's Home (which we know to be a brothel!).
Pastor Manders worries that he won't be in charge of anything much longer, if it gets out that he had a hand in the fire.
But Engstrand has a solution for that. He will take the blame on himself, just as he did with Johanna. Pastor Manders, after a moment of hesitation, accepts the offer. They will travel together.
Engstrand tries to get Regina to come, too, but she haughtily refuses.
It's no matter. Engstrand will name his brothel "Chamberlain Alving's Home" – and will guarantee that it's a fitting memorial to Oswald's late father.
Oswald has come in. He's disheveled and feverish. Mrs. Alving recognizes that he is seriously ill. This is news to Regina.
Mrs. Alving has some news, too. She sits both youngsters down to talk to them. Once she's finished, she thinks Oswald's mind will be relieved.
Inspired by Oswald's explanation of the joy of life, Mrs. Alving sees her husband in a different light. She describes him as an innocent, high-spirited man who was destroyed by living in a backward town. She acknowledges her own role in contributing to his ruin, wedded to the idea of duty as she was.
Then she comes out with two big wallops: Oswald's father was sick too. And he was also the father of Regina.
Regina doesn't waste any time. She wants out. She's not going to stay here and take care of sick people. She's got to get on that steamer as fast as she can, whether it means pursuing something with Pastor Manders, or working at the Sailors' Home.
So Mrs. Alving is left alone with her son. She checks in: is he terribly shocked to learn that his father was so miserable?
Oswald doesn't care. He doesn't feel any filial obligation – to his father or to her.
But Oswald does need her to relieve him of the dread. Now it's his turn to sit her down. He has a request.
Oswald explains that he will suffer an attack that softens his brain for good, making him a vegetable. It's the one thing he can't stand.
He takes a little box from his pocket: morphine. This is why he wanted Regina here. She would have gotten sick of looking after an invalid, and would have used the morphine to put him to rest.
But now she's gone, so he turns this request over to this mother.
Mrs. Alving totally flips her lid. She gave him life; she can't think of taking it back. She tries to run away but he locks her in. He begs her.
She agrees. But thinks it will never be necessary.
All he needed was that promise. He can relax now.
Day is breaking. Mrs. Alving gives her boy a speech of comfort, and puts out the lamp.
Suddenly Oswald says, "Mother, give me the sun" (3.259).
Mrs. Alving is confused.
He repeats, over and over, "The sun." His muscles have relaxed, his eyes are glassy. It's happened.