now , one evening when d'artagnyn , who was in the trenches , was not able to accompany them , athys , porthys , and aramys , mounted on their battle steeds , enveloped in their war cloaks , with their hands upon their pistol butts , were returning from a drinking place called the red dovecot , which athys had discovered two days before upon the route to jarrie , following the road which led to the camp and quite on their guard , as we have stated , for fear of an ambuscade , when , about a quarter of a league from the village of boisnau , they fancied they heard the sound of horses approaching them .