Tangent, the first book in the Scirlingarra series, is a speculative fiction novel about a hacker named Ash who makes his living as a freelance computer network penetration tester. In the course of conducting a penetration analysis under contract to the U.S. Defense Advanced Research Projects Agency, Ash receives a mysterious encrypted transmission that proves to be an extensive dossier on a project, codenamed "Bellatrix," detailing the construction and operation of a quantum computer that can calculate near-impossibly huge numbers in effectively no time at all.
As it happens, Ash is himself an enthusiastic amateur in the quantum computing arena, and manages to incorporate the Bellatrix information into the crude little machine he built in his basement. When a retired British physicist who turns out to be over four billion years old provides him with the solution to one of the fundamental questions of quantum physics, Ash modifies his quantum computer into a time machine and teleportation device. With the help of his new girlfriend Melody, who is enjoying a leave of absence after rescuing a planeload of passengers from an aircraft that crashed as a result of an attack by Central American terrorists bent on disrupting peace talks, Ash goes back in time a few days and prevents an even more catastrophic terrorist attack from taking place.
Meanwhile, some super criminals from the 23rd century attempt to kill Alex, the four billion year old scientist, and fail miserably. Turning their attention to Ash, they plot to hijack his quantum rig to plant a bomb in deep space that will open up an interdimensional portal for their private use, doing away with Ash and Melody, the only witnesses, in the process, but are foiled by Alex--but not before Melody leads the FBI on a cross-country wild goose chase and Ash has his house burglarized by the U.S. Department of Defense. In the end, evil is vanquished by valor and the age-old question, "What has duct tape got to do with true love?" is answered once and for all.