Back at the robot thing, Madge's sobbing has affected the workers. After some comedic arguing, they decide to lay down their weapons and make their introductions. They're from Androzani Major in the year 5345. Madge introduces them to the gun she's been hiding in her coat. "Crying's ever so useful, isn't it?" she asks with a sly smile.
The Doctor isn't having much luck getting to Cyril because he can't sonic his way past the wooden door. Lily points to a window and to the trees beyond as thousands of lights rise up out of their branches. The Doctor calls it "pure life force." Lily is so awed that she cries a bit. "Crying when your happy," the Doctor says, "good for you." He gives her shoulders a squeeze. "That's so human!" Inside the dome, the tree lady places the circlet on Cyril's head. Treebeard gets up creakily from his throne and clomps his way upstairs.
Madge has gotten the woman worker to tie up her coworkers in the cockpit of the robot thing. Madge recognizes it as a cockpit because, as she says, her husband was a pilot. I can't see much similarity between a 1941 airplane and anything from 5345, but whatever. The woman then goes to the computer to scan for Madge's children. The others tell her that the forest is about to be "harvested," because Androzani trees are the greatest fuel source ever. "The entire area is being melted down for battery fluid." This will be done by the acid rain that's due to fall in five minutes.
The Doctor and Lily get into the dome and find Cyril unconscious. Through a window, they see the life force leaving the trees and heading for the dome. Cyril rouses and speaks for the wooden king and queen. "They're scared. Can't you hear them? The trees are screaming."
Madge's sympathizer has found life signs in the forest a half mile away, but she's not trained to drive the platform so they're stuck. Madge looks around, decides it looks like something like a plane cockpit and since her husband took her up in his plane once, she can figure it out. I don't have time to go into how crazy dumb that is, so let's move on. The sympathizer makes an audio connection so Madge can hear her children but then all the workers beam out, leaving Madge and the others to deal with the acid rain. Madge hears Cyril channeling the trees, saying that they're evacuating ahead of the "rain that burns." The Doctor helpfully explains that the life force, the souls of the trees, need to travel inside a living thing. The circlet is a relay. The tree queen touches Cyril and he speaks with her voice: "Your coming was foretold. We waited and you came." Alas, Cyril is weak, she says. The Doctor volunteers to be the lifeboat, but the trees pronounce him too weak, as well. The Doctor, miffed, grabs the circlet off Cyril's head. It glows and burns the Doctor, but he can't let go, so Lily snatches it from his hands. It doesn't harm her. The tree queen touches her. "She is strong, but she is young." The acid rain begins to fall. In the platform, Madge hears her children. They have faith their mother will come for them.