A brief promo and several new stills have been released for this week’s new episode of The Big Bang Theory, previewing what looks like an experiment gone awry.

After taking last week off, The Big Bang Theory will return on Thursday night with “The Contractual Obligation Implementation.” A new promo for the episode gives us a quick glimpse at an unhappy Sheldon – and several teenagers who appear to feel the exact same way. Check out the promo right here:

Photos released from the “The Contractual Obligation Implementation” also focus on the travails of Sheldon, Leonard, and Howard as they return to a junior high school setting – one which undoubtedly calls back, er, one or two happy memories for the lifelong geeks. The stills also hint at the episode’s other plotline, Raj’s attempt to woo Lucy, his ill-fated Valentine’s Day date. Check out the stills right here:

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Just keep in mind Raj, you promised Lucy you would sweep her off your feet with your own craziness; Sheldon may have a few tips, if you need them.

CBS’ official summary for “The Contractual Obligation Implementation” says:

Leonard, Sheldon and Wolowitz speak to junior high girls about careers in science. Meanwhile, Koothrappali plans a date with Lucy.

And next week on The Big Bang Theory, “The Closet Reconfiguration” will air.

Howard struggles with whether or not he should open a letter from his father, and Leonard and Penny throw a “grown-up” cocktail party at the apartment.

What are your hypotheses for “The Contractual Obligation Implementation”?