The night has a thousand eyes
The walls have a hundred ears
And I have but a fleeting moment
To spend eternity with you

It's a story of two star crossed lovers who are on the run and are being pursued by the parents and relatives of the girl and by a rich and very powerful man and his henchmen.

The girl was betrothed to the rich and powerful man through the machinations of her greedy parents. The two lovers met at a public inn to spend their last night together, fearful of being caught by the angry mob.

They could actually feel that the night has a thousand eyes and the walls have a hundred ears, so they concealed themselves in the darkness of the night and whispered in hushed voices their undying love for each other.

They have just this one fleeting moment to make love for the last time and end their lives together. Reminiscent of the tragic love story of Romeo and Juliet, isn't it?

So there goes the answer to the riddle.
One Love - The Carpenters (1971) USA