The speaker starts with a question: what if someone chose to swim a river rather than cross by bridge, then climbed out cold and dripping and turned down every towel and fire in favor of being alone? Almost at once the question flips. What if that swimmer had no choice, and some outside force pushed them into the water? From there the poem imagines the bridge disappearing, the river swelling into an ocean or a widening gulf, and every boat turning into a sieve. Buses and bikes are gone too.
The speaker calls this "a strange country," one that holds opposites together: poverty and wealth, choosing and being forced, truth and fiction. The tone is thoughtful and a little uneasy, since the poem keeps unsettling its own picture. The ending is gentler, though. In our minds, the speaker says, there is a place that welcomes all drifters. The poem suggests that imagination can offer shelter even when the journey is lonely or not freely chosen.