This is the longest of lovecrafts stories and the best example of how his tales build tension, and the atmospheric horror he was famous for. Told in a first person perspective, at the mountains of madness recounts a failed expedition to the vast unexplored lanscapes of Antartica. Shortly after arriving at their campsite, one of the group sets out on a solo trip in one of the planes. He sends word to the rest of the party that he has made several amazing discoveries, discoveries that defy belief. He relays several updates back to an excited camp and informs them of large, apparent fossils which he has managed to make ready for the return flight, but which seem to set the huskies on edge.
Soon after the contact stops, leaving the party no choice but to set out on a rescue mission. As the two man rescue party finally spot the landing site of their missing member and land the plane, they are met with a scene of disturbing signs.
From this point on, Lovecraft builds the terror expertly but never shows the creature or presence that is overshadowing every step the explorers take. The setting of Antarctica is used as one of the characters in this tale to great effect. Lovecraft uses the isolation as a sharpening stone to the growing paranoia of the explorers.
This is a master of atmospheric horror at his best!