These two friendly delivery boys from a Parisian department store not only take their job to heart as much as possible, but also consider themselves responsible for the happiness of the customers they have to deliver to. This leads them successively to help, at the cost of incredible acrobatics, a young couple celebrating the first anniversary of their marriage, to mingle with the clientele of a rather disquieting doctor, to almost perish in an ambush that was of course not intended for them, and to avoid a domestic quarrel.