Several people live in a cluster in an otherwise remote area.
One of them, a woman, romantically writes a note of declaration of her feelings for another resident on a piece of paper, "I love you, Roberta." She tapes her note to the side of his small seaplane shortly before he leaves.
The man, in a hurry, gets in without noticing the love note, and flies off for his journey.
Upon returning, the woman watches for his response. As he gets out, he finally notices the note, now torn. It has lost its "A" and appears to be signed by "Robert," something she cannot see from her window far away from the dock. The man shows up, not at her door, but the other neighbor, who is a bit confused.
The pilot addresses the other man with the words "Ich wusste ja nicht..." ("I did not know..."). The short word "ja" cannot be translated but in German it indicates a (here unspoken) second sentence continuing "... but if I knew..." That makes possible a wider scope of speculations about the men's relationship.
The tagline of the ad ("Keine halben Sachen") means "Don't do things by halves."