As soon as he could leave the hospital he went to Arisia in the hope that he might be permitted to take advanced training--an unheard-of idea. Much to his surprise, he learned that he had been expected to return for exactly such training. Getting it almost killed him, but he emerged from the ordeal infinitely stronger of mind than any man had ever been before; and possessed of a new sense of perception as well--a sense somewhat analogous to sight, but of vastly greater power, depth, and scope, and not dependent upon light, a sense only vaguely forecast by ancient experiments with clairvoyance. After trying out his new mental equipment by solving a murder mystery upon Radelix, he succeeded in entering an enemy base upon Boyssia II. There he took over the mind of the communications officer and waited for the opportunity of getting the second, all-important line upon Boskonia's Grand Base. An enemy ship of this base captured a hospital ship of the Patrol and brought it in. Nurse MacDougall, head nurse of the captured ship, working under Kinnison's instructions, stirred up trouble which soon became mutiny. Helmuth, from Grand Base, took a hand, thus enabling Kinnison to get his second line. The hospital ship, undetectable by virtue of the Lensman's nullifier, escaped from Boyssia II and headed for Earth at full blast. Kinnison, convinced that Helmuth was really Boskone himself, found that the intersection of his two lines--and therefore the pirates' Grand Base--lay in a star cluster AG 257-4736, well outside the Galaxy. Pausing only long enough to destroy the Wheelmen of Aldebaran I, the project in which his first attempt had failed so dismally, he set out to investigate Helmuth's headquarters. He found a stronghold impregnable to any massed attack the Patrol could throw against it, manned by beings each wearing a thought-screen. His sense of perception was suddenly cut off--the pirates had thrown a thought-screen around the entire planet. He then returned to Prime Base, deciding en route that boring from within was the only possible way in which that stupendous fortress could be taken. In consultation with Port Admiral Haynes, the zero hour was set, at which time the massed Grand Fleet of Patrol was to begin raying Helmuth's base with every projector that could be brought to bear.