'EXOGENOUS' Part 4 of 5! - As the X-Men race to find the origins of the threat that has emerged from deep space, they discover that there's a larger conspiracy at workone that may have its roots close to home! - What are Agent Brand's ties to the mysterious Providian order? - How could Deathbird's secret upset the balance of the cosmos? - And what does the third Summers brother-and Rachel Grey's uncle-Vulcan have to do with it all? Rated T+