Through the Gates of the Silver Key

"Through the Gates of the Silver Key" is a short story co-written by H. P. Lovecraft and E. Hoffmann Price between October 1932 and April 1933. A sequel to Lovecraft's "The Silver Key", and part of a sequence of stories focusing on Randolph Carter, it was first published in the July 1934 issue of Weird Tales.
At a gathering to decide the fate of Randolph Carter's estate (which has been held in trust since his disappearance) the mysterious Swami Chandraputra, who wears curious mittens and enveloping robes, tells Carter's acquaintances of his ultimate fate. He explains that after performing its ritual, the Silver Key took Carter to the Outer Extension, a realm transcending spacetime, by transporting him through a cosmic structure known as the First Gate. There, Carter met the Ancient Ones, a group of mystic beings led by 'Umr at-Tawil, a dangerous being warned of in the Necronomicon, saying those who deal with it never return. 'Umr at-Tawil offers Carter a chance to plunge deeper into the cosmos; after Carter accepts, the Ancient Ones manifest and open a structure known as the Ultimate Gate, which takes him to a truly infinite void...