Just after agreeing to an ultimatum offered with the cartel, Gus requires Mike and Jesse down with him to Mexico, in which they may have Jesse teach the cartel scientists (led by Benicio Fuentes) how to cook the blue meth. Gus returns from Mexico and his romance with Walt unravels, https://tituspurss.dreamyblogs.com/29912092/little-known-facts-about-blue-crystal-math