"It's curious," said Shears. "I seem to hear noises in the house."
"In the house? Impossible! Everbody's asleep."
"Listen, though...."
At that moment, a faint whistle sounded from the railings and they perceived an undecided light that seemed to come from the house.
"The d'Imblevalles must have switched on their light," muttered Shears. "It's their room above us."
"Then it's they we heard, no doubt," said Wilson. "Perhaps they are watching the railings."
A second whistle, still fainter than the first.
"I can't understand, I can't understand," said Shears, in a tone of vexation.
"No more can I," confessed Wilson.
Shears turned the key of the door, unbolted it and softly pushed it open.