American GI Ernie Williams, admittedly weak-kneed, has an uncanny resemblance to British Colonel MacKenzie. Williams, also a master of imitation and disguise, is asked to impersonate the Colonel, ostensibly to allow the Colonel to make a secret trip East. What Williams is not told is that the Colonel has recently been a target of assassins. After the Colonel’s plane goes down, the plan changes and Williams maintains the disguise to confuse the Nazis about D-Day.

When churlish, spoiled rich man Bob Merrick foolishly wrecks his speed boat, the rescue team resuscitates him with equipment that’s therefore unavailable to aid a local hero, Dr. Wayne Phillips, who dies as a result. Phillips had helped many people, and when Merrick learns Phillips’ secret, to give selflessly and in secret, he tries it in a ham-handed way.