Fifth in the Apprentice Adept series (Out of Phaze, 1987), an overextended mega-yarn that now looks decidedly shabby and increasingly threadbare. Once again, young robot Mach of science-world Proton exchanges minds with young magician Bane of magic-world Phaze. This time the pair succeed in exchanging their girlfriends, too--but all this popping back and forth through the barrier that separates Phaze from Proton is causing the system to become unstable. The lads are unsure whom to throw their lot in with: The Adverse Adepts guarantee Bane's and Mach's rights to marry their respective loves, but also threaten to take over both Phaze and Proton; Stile, the Blue Adept, and his good-guy allies will set things to rights, magic and technology-wise, but refuse to countenance Bane's marrying a unicorn or Mach's an ameboid blob. To settle the matter, Mach squares off against Bane in a stylized games-playing contest: if Mach wins, they ally with the Adverse Adepts; if Bane wins, they go along with Stile. The first trilogy, featuring Stile and his quest to become Citizen and Blue Adept, was endlessly inventive and absorbing; the second time around--sons of--that magic has evaporated.