This gift is apparently random, and can range from a minor telekinesis limited to lifting pencils to super-enhanced senses to teleportation to full conjuration of matter.
The main character, a philosophy major from Earth named Gene Ferraro, gains the power of superb swordplay.
His best friends include Snowclaw, a giant humanoid covered in white fur, who originally comes from a polar-like clime, and Linda Barclay, a woman from Earth who becomes a powerful sorceress.
However no one has a map, or knows where the Skyway begins or ends, and because each portal is one-way, only explored sections with a known return path (discovered by trial and error) are considered safe to travel.
At the beginning of the first book Jake finds himself in trouble because a number of parties, both human and alien, are convinced that he has found a map.