乔治（詹姆斯•斯图尔特 James Stewart 饰）在圣诞节前准备自杀，这时上帝传来旨意，派天使拯救他，并让他了解到自己一生的使命——拯救那些不幸的人。乔治小时候左耳有疾，在贝德福德镇上的一家药店帮工。他很机灵，深得老板器重，同时也很招女孩喜欢。某日，老板接到爱子死亡的电报，悲痛欲绝，配错了药，幸亏乔治才化险为夷。乔治从小嫉恶如仇，尤其看不惯富人专横跋扈。长大后，乔治一表人才，准备去读大学。这时，他的父亲去世了，他子承父业，协助叔父料理公司事务。然而公司经营状况不佳，在董事会会议上面临破产。如果公司破产，小镇将会有很多家庭陷入困境。乔治力排众议，说服了董事会，但是条件是他要担任董事会秘书长。这与他的大学梦相去甚远。而且，此时他还陷入了对一个女孩的爱恋之中……

A poor cobbler's son enters a $25,000 cross-country hiking contest sponsored by the footwear company that has nearly bankrupted his father. He also has fallen in love with the girl on the company's billboards, the competition's daughter, and her sweet inspiration keeps him tramping along.

Molly Kelly, a cigar stand drudge, marries the wealthy son of a restauranter who (as a result) disinherits his son. Later the son "makes good" by opening a lunch box stand and his father, whose business has fallen off, gives the young couple financial help to expand their business. An early effort from director Frank Capra (IT'S A WONDERFUL LIFE), THAT CERTAIN THING is a glimpse at the cinematic beginnings of this great filmmaker (and, therein, warrants some accommodating on the part of the viewer for the well-worn print).