This review may contain spoilers.

As the episode title suggests, this weeks latest in Chuck (Zachary Levi) and Sarahs (Yvonne Strahovski) seemingly never ending relationship woes comes in the form of a cubic zirconium engagement ring.

The ring itself belongs to Big Mike (Mark Christopher Lawrence) -- he wants to propose to Morgans (Joshua Gomez) mother -- but the laws of serendipity eventually have it land in Chucks hand in the middle of a conversation with Sarah about what future aspects of their relationship shed be comfortable with.

Former villains Heather Chandler (Nicole Ritchie, Chuck Versus The Cougars) and Hugo Panzer (Stone Cold Steve Austin, Chuck Versus First Class) return to be a pain in Chucks romantic and professional lives, respectively. While Panzer escapes to get his revenge on Chuck, Heather Chandler tags along for the ride, taunting and teasing Sarah the way she has been since high school.

What Worked

Nicole Ritchie reprising the role of Heather Chandler may have ultimately just been another obstacle in the Chuck/Sarah relationship saga, but the character is such a good foil to Sarah (or Jenny-Sarah if you ask Heather), that its easy to ignore and just enjoy the interaction.

The Buy More storyline continues to be more interesting than the A-storyline, especially with Morgan in a position of power. The return of Big Mike not only brought the laughs, but it led to the demise of Panzer, a villain who wasnt really all that interesting the first time around.

What Didn't Work

Is it too much to ask for the writers remember that Chuck has more in his life than his relationship with Sarah? Yes, his sister is pregnant with a child that is bound to be awesome, but even that storyline is being used as a reason to drive a wedge in the Chuck/Sarah relationship. Theres a reason why the spark of Chuck is gone, and this might just be it.

Also noteworthy -- Stacy Keibler played this weeks Greta. That went about as well as you would assume Stacy Keiber playing Greta would go.

Giving Credit Where Credit Is Due

"Chuck Versus the Cubic Z" was written by Nicholas Wooton and directed by Norman Buckley. Chuck stars Zachary Levi, Yvonne Strahovski, Joshua Gomez, Mark Christopher Lawrence, Scott Krinsky, Vik Sahay, Bonita Friedericy, Ryan McPartlin, Sarah Lancaster, Adam Baldwin.

"Chuck" airs Mondays at 9 p.m. ET on NBC.