Popular in the riverside area of Porto, Micas raised her daughter, Madalena, at the cost of sacrifice, as her father emigrated to Brazil. With a happy voice, Madalena works on unloading the coal, seeing her loves thwarted by her humble condition. Barata, another typical figure who makes a living from expedients, helps Madalena's father - meanwhile returned, to "register" her - in a kidnapping plan capable of facilitating her reconciliation with Micas, who is reluctant... Things get complicated, but happiness ends up triumphing.