Crotchety retired doctor Isak Borg (Victor Sjöström) travels from Stockholm to Lund, Sweden, with his pregnant and unhappy daughter-in-law, Marianne (Ingrid Thulin), in order to receive an honorary degree from his alma mater. Along the way, they encounter a series of hitchhikers, each of whom causes the elderly doctor to muse upon the pleasures and failures of his own life. These include the vivacious young Sara (Bibi Andersson), a dead ringer for the doctor's own first love.