This week’s crisis was a good one, but we’ll get to that in a minute. The primary focus of this episode was relationships, and ‘Eureka’ is one of those rare shows that can have character relationship issues that don’t feel forced or silly. This week, the four major relationships of the season – Carter and Allison, Henry and Grace, Zane and Jo, and Fargo and Holly – all get a bit of a shakeup.

Still unsure about Allison, the DOD has sent in an auditor to examine her relationship with Carter “for national security.” The auditor, Warren Hughes, played by Wallace Shawn (yes, Vezzini and the Grand Nagus Zek himself!), is assigned to spend a day following them around, jotting notes down on a little clipboard. And, of course, this is the day that the once-killer rover Tiny returns from a recon trip to Titan – made nigh instantaneous thanks to the FTL – and then promptly explodes. Just another day in Eureka, folks.

On the other relationship fronts: Fargo and Holly are having difficulty with their Titan training due to their own sexual tension. Holly gets the bright idea of the two of them just having sex and getting it out of the way so that they can concentrate on the mission. Fargo, however, is still a romantic at heart and wants the relationship buildup before that moment. Henry and Grace are well into planning their own wedding, and Henry becomes disheartened by the fact that Grace wants new wedding rings as opposed to using the old ones that Henry said he hoped to one day earn. And Zane and Jo, still unable to express any feelings other than those of the pelvic variety, have to deal with their own unspoken tension as Zane is officially given a pardon and made eligible for Astraeus. Jo expresses her own discomfort by diving headfirst into planning Henry and Grace’s wedding, while Zane deals with his share of it by trying to give Fargo some overly-manly advice regarding his relationship with Holly. It’s the world’s dorkiest and most awkward soap opera, and it couldn’t be more enjoyable to watch.

Now to the crisis of the week. After Tiny’s sudden and unexpected destruction, gasses from Titan suddenly begin descending upon Eureka. Thinking that Tiny had brought it back from Titan, the gang soon discovers that the technician in charge of the all-too-accurate Titan simulator has been flushing away one concocted environment after another until the disposal tank ruptured and began spilling its contents all over the town. The thing about Titan’s atmosphere is that it’s high in methane and so many other volatile chemicals that, when combined, can be pretty toxic and…well…explosive. It’s up to Fargo and Holly to work through their tensions so that they can team up and use their Titan training to go into town and flush the Titan atmosphere out of the town before it suffocates and/or blows everybody up.

The somewhat unexpected and quite heartbreaking twist comes at the very end at Henry and Grace’s wedding. Warren, who is also an ordained minister, officiates the wedding, but not before telling Carter and Allison that they have to break up. According to his assessment, they care about each other too much, and it presents a liability. This is what I like about ‘Eureka.’ When they throw you a curveball, it tends to go straight for the gut. After all these years of tension, when Carter and Allison finally get together, the government steps in and tells them they can’t be together. The preview for next week shows that Warren will be sticking around Eureka for a while. Let’s hope he sees the error of his decision.