Mina is out on a herb collecting trip along a canal a few miles from home, when she meets a bargeman called John Millen. He is trading along the canal using a horse-drawn barge. The two strike up a friendship immediately. Among his goods are a quantity of rubber
boots. Mina arranges to meet the barge the next day to set up a trade for some of the boots.Next day, the barge arrives early. Some of the community go down to meet it, but Mina is preparing lunch for Millen, so does not go down immediately. There are two men on the boat, called Kane and Grice. Kane is wearing Millen's hat. They are surprised at the reception comittee, but bluff their way through the situation, and as no-one else had seen the barge
before, get away with this. Pet however thinks she has seen one of them before...
The men are an ex -prisoner and one of his warders. Kane is obviously a bad lot and prone to violence. They take advantage of the settlement's hospitaility. Grice feels uneasy about the situation, but Kane wants to stay around - he says he wants to look around to case the joint.
When Mina eventually meets them they have to lie, saying Millen had had to return to their
settlement as his wife was ill. Mina is suspicious as Millen had told her he was unmarried.
Greg and Lewis the parson go to the barge to pick out boots for everyone. They find many varied items on the barge, including guns and barrels of wood alcohol. Pet eventually remembers Kane - her father had been on the jury which had convicted him of murdering a guard in an armed robbery several years before. Mina meanwhile searches back along the canal, and finds
Millen's body floating face down with a knife in its back. She goes back and confronts the pair. They don't deny the killing and make a hasty exit from the main house, however since it is evening they return to the quarantine hut where they are quartered for the night.
Charles and Greg decide to go to the barge and retrieve the weapons there in case the two try anything violent, although they have guns with them in the hut. In the morning, Greg and
Charles go armed to the hut to evict the men. Lewis stops them, saying he wants to try to ask them to leave peacably. However the men have taken the children hostage, and demand horses immediately. They threaten the kids, and to show they mean business, Kane shoots Lewis, killing him. Greg and Charles fetch their horses. The men take the children with them and ride back to the canal. Greg and Charles follow at a safe distance. The take the barge and
begin to move away, but start drinking the wood alcohol, not realising its dangers. They begin to feel ill and the kids manage to slip of the boat. They pull the barge over to the side and go below - they light a match for light, and the wood-alcohol fumes in the barge cause an explosion, taking them with it.
