This article may contain spoilers.

Just when Claudia Donovan (Allison Scagliotti) from "Warehouse 13" visits Eureka, a few exotic particles from the time-travel trip to 1947 awaken to pull things from the past and start inserting themselves into the present. As if five Sequoia redwood trees springing up in Global Dynamic's lobby were not enough, an airplane appears in Cafe Diem, a fence and a mine field show up outside of town, and a bullet appears in Jo's chest. The merging of the two realities meant that time would ultimately collapse in on itself because two things cannot exist in time and space simultaneously.

So it was another race against the clock episode until they could identify the source of the exotic particles that was acting as a magnet drawing things through the wormhole. When it turned out that Dr. Charles Grant (James Callis) was carrying the exotic particles in his body, he became a ticking time bomb.

As a nice coincidence, this also happened to be the very day that Allison (Salli Richardson-Whitfield) decided it was time for Dr. Grant to stop smoking. But it turned out to be a good day to stop smoking as the nanobots used to purge his blood stream of nicotine could be reprogrammed to purge his body of the exotic particles -- thus preventing the universe from imploding. So quitting smoking is not only good for your own health and those around you, it can also save the universe from collapsing as well.

What Worked

All the wrinkles in their personal relationships are continuing to preoccupy them: Jo (Erica Cerra) is still mourning the loss of her relationship with Zane (Niall Matter); Jack (Colin Ferguson) is still chafing under his indecision on how to pursue a relationship with Allison -- especially with Charles also intent on pursuing her; and Henry (Joe Morton) is uncertain what to do about suddenly having a wife. Only Fargo (Neil Grayston) seems to be putting the best foot forward and taking a risk by trying to make his feelings known to Claudia. (Special mention should be made that Allison Scagliotti as Claudia provided a nice foil for Fargo and was a fun addition to this week's wacky adventures.)

But, by far, the best fun to be had was watching everyone squirm and struggle with what's next in their lives. Since Jo's home was destroyed in the last episode, it was fun to get a glimpse into what it is like now that she and Jack are living together. Surprisingly, they are like college roommates attempting to numb their mutual pain and frustration over their respective love lives by watching reality TV shows. Jo's quip about them sharing "girl talk" which Carter tried to describe as purely "guy talk" was priceless!

It was also cool that Allison got Jo and Jack bonding - understanding that Jack would be lonely with both Tess (Jaime Ray Newman) and Zoe (Jordan Hinson) gone and thus liked having Jo around for the company. Though Jack was reluctant to admit it and finally sheepishly said, "Maybe. Don't tell Jo," as Allison promised not to with a broad smile.

On the flipside, it was good to see that Jack is chafing under the constraints of having Charles making a play for Allison, just when it should be Jack's turn. Jack's indecision about making a move has cost him before and it may again if he does not step up and declare his feelings for Allison.

Henry is also increasingly frustrated with his situation with Grace. She is in love with a man that he no longer is and she is clinging to a past that no longer exists. Despite his attraction to her, Henry is reluctant to jump into a relationship with a woman under false pretenses -- which makes him feel like he is taking advantage of the situation. However, Henry is also beginning to suspect that he may not have a future without her. So when Grace confronts Jack about Henry, she wants to know what has changed. As she observed, "We used to be partners -- I just want my husband back." Henry's indecision may also cost him a wonderful woman if he does not figure out what he wants soon too.

As for Jo and Zane, things may be looking up as Jo awakened from emergency surgery to find Zane sitting at her bedside. As he sat there watching over her, it looked like he was trying to fathom what she saw in him. He too senses that something is different about her - for this is not the woman who delighted in making his life miserable and harassing him. This new Jo clearly has feelings for him and he is at a loss as to why. So the look he gives her as she slept was a mix of wonder and tenderness. It was a glimpse into the Zane that Jo knew and loved. Thus, when she wakes and finds him there, she must have thought she was dreaming and asked, "What are you doing here?" Zane smiled and simply said, "I heard what happened. For the record, it wasn't me." It hinted at a ripening future between them.

Finally, it was nice to see that Charles' chain-smoking was addressed and that they wrote in a story-line that deals with helping him quit smoking -- making a point to emphasize that it is dangerous not only for him, but also to those around him. It was a nice touch when he tried to hit on Allison and she wisely noted, "Seems like you're trading one vice for another." To which he quipped, "Trust me, I have an endless supply of vices for you to cure." Allison may want to help Charles and may be charmed by him, but it seems unlikely that she wants to get involved with a man who constantly needs saving from himself.

What Didn't Work

The colloquialisms need work. The "what's up, bitches?" phrase that Claudia said when she first arrived in Eureka was highly offensive and out of place given the tone of "Eureka." Plus, it is doubtful she would have actually said that upon just meeting people she wanted to impress in Eureka -- after all, she was Fargo's (the head of Global Dynamic) honored guest.

Plus, when Claudia stepped on a landmine, she frustratedly said, "I do inventory, not bomb disposal!" To which Fargo retorted, "What do you think my job is -- the Hurt Locker?" It also felt jarring to make a film reference right in the middle of this scene. It took the viewer out of the scene which could have been either dramatic or funny, but because of the film reference just felt out of place.

The one time the colloquialisms kind of worked was when Claudia noted that she and Zane both had the same last name, and she sweetly said, "coincidence?" To which Zane archly responded, "There is no such thing, sweetheart."

Giving Credit Where Credit Is Due

"Crossing Over" was written by Paula Yoo and directed by Michael Robison. "Eureka" stars Colin Ferguson, Salli Richardson-Whitfield, Joe Morton, Jordan Hinson, Erica Cerra, Neil Grayston, Chris Gauthier and Niall Matter.

"Eureka" airs Fridays at 9 p.m. on Syfy.