Captain Wilson (we never learn his first name) runs a small steam boat on the river Kuna in the fictional West African state of Borami. He is taking it from the port of Ekondo to the capital Tandeko on the day that a British royal personage and the new President will travel by train to independence ceremonies. Also on the train is the woman Captain Wilson loves and hopes to marry. But a sinister Greek passenger on his boat draws a gun on him and reveals he has plans to sabotage a railway bridge as the train is passing. At the same time his African hand, who has smuggled his wife on board to get her a free passage, tells him that she is about to give birth. Will the criminals' plans be thwarted and the baby be delivered in time? Well, of course they will, but I am not telling you how.
The situation was highly topical, since Ghana had become the first African colony to be given independence in March 1957. The central characters owe something to The African Queen, while the plot is pure Boy's Own Paper.