Miss Marchant is arguing with Miss Appleyard in her office. She feels that not only is Miss Appleyard encouraging Maggie and the other girls but enabling them. Maggie is called in is told that she must apologize. She is defiant but Miss Appleyard assures her that, "to win a big war, you must lose a few small battles." Angry and humiliated, Maggie apologizes. Some boys, including Henry, are trying to get through to Jack. With all the talk of the swimming he is terrified again. Finally, he lets loose and explains where the fear comes from. Back at home, his siblings were never around and he was often alone with his mother. She did not like him and used to lock him in a cupboard. Even worse, she used to hold his head under water until he couldn’t breathe. Many of the children wonder to themselves what it is like to have a mother who truly loves you. ("What's it Like to 'Ave a Mother") The troublemakers have gathered again and have a plan in motion. They will get treacle toffee from the mines near the home and send it to Dick's friends in London for a profit. They are not worried about the war; they plan to become rich with their scheme. Meanwhile, Maggie and Henry are at the lake with Jack for his swimming lesson. He hesitates at first but once he is in and going they are amazed at what a natural he is. He seems to have conquered his fear and is even a very good swimmer. Geordie is there too, and they all tease Henry about not having swum across the lake before. Jack jokes that he will swim with him and will hold his hand when he does the swim at the exhibition. The boys have arrived with the Maypole to set up for the next day's festivities. Geordie is looking for Jack and Maggie whispers to him that he is out swimming with Henry. He swam a mile and a half the day before. There are claps of thunder-a storm seems to be moving in. They are worried about being able to swim; by the lake there tend to be electrical storms with lots of lightning. Finally, the three boys who will join Henry on the swim are announced. The troublemakers are convened at the train station. They are going to ride up to the mine, stock up and bring back the loot to send out on the next train. Hannah, one of the girls involved, runs in and tells Joss that she just found out the mine is not a treacle mine but is filled with gunpowder. There is an electrical storm going on and the boys are probably smoking. They are in great danger in a mine filled with gunpowder. The two rush off to catch the other boys. Alarms are going off at St. Michael's and all the boys are gathered for a roll call. There has been a huge explosion at the mine and two bodies were found. They find out that Dick and Midgeley, his partner in crime, are missing. Joss and Hannah have been brought in and Hannah, in a panic, tells everything and blames it on Joss. The staff are gathered that next morning in the office. They cannot believe the night that just occurred. One boy is dead and one is critical. The children send a representative to tell the staff that despite what has happened they wish for the day’s activities to continue. The staff agrees that they, too, would like to see this happen. The Spratt children along with Maggie come in and are informed that their brother has been killed. Jack explains that Midgeley was supposed to have been swimming and that he wishes, as a tribute to his brother, to swim in his place. All gather at the lake, and the festivities carry on as planned. There are great performances and much rejoicing as well as a few somber moments to remember the boys who were in the accident. Then the swimmers take their place. Henry and the other two boys dive in leaving Jack trembling on the side. He summons the courage and dives in. Maggie is sitting in her hospital tent back in 1918 in the thick of the war. She is writing a letter to Henry about how she is where she wanted to be but they are all tired of war. She imagines that she is very near him and just hopes that this will be over soon. Just then, Henry, led by Spratt push through the warfare and arrive at the hospital tent. Spratt lies Henry down; he has shrapnel in his leg. At first none of them recognize each other then slowly they realize. The three are reunited again.