Shattered Lives (1925)

Elizabeth Trent lives alone on a farm with her adopted son, Donald, having been deserted by her husband, John, years earlier when he went to Alaska to make his fortune. When Trent decides to return to his family, a shyster named Spencer Foulkes, who knows that Elizabeth's real son has been lost for years, persuades Red Myers, an unpleasant city youth, to impersonate the missing boy and thus inherit John Trent's fortune. Trent later falls into the hands of Foulkes, and Don saves him from certain death, reuniting him with Elizabeth. It then turns out that Don is in fact the son of the Trents, having been adopted by his own mother.