CBS offers some new details about how The Big Bang Theory and Young Sheldon crossover episode will work, despite their differing time periods. Next spring, The Big Bang Theory will air its series finale, after 12 seasons and nearly 300 episodes produced. Co-created by prolific sitcom producer Chuck Lorre, Big Bang prepares to sign off on top, standing as easily the #1 rated comedy on TV. While the show has its share of haters, to call The Big Bang Theory any less than a huge success would be disingenuous.

Last year saw The Big Bang Theory’s universe expand, with the introduction of single-camera spinoff Young Sheldon, also co-created by Lorre and also airing on CBS. While the tone and style of Young Sheldon is quite different from its progenitor, many fans have gladly added it to their viewing schedule, and critics have actually tended to enjoy Young Sheldon more than Big Bang. While Big Bang Theory is soon to end, there’s no telling how long Young Sheldon might continue to carry on the franchise going forward.

Earlier this month, it was announced that characters from Young Sheldon would be appearing during an episode of Big Bang Theory’s final season, in a crossover event. At the time though, CBS was completely mum on how exactly the crossover will occur, as Young Sheldon takes place decades prior to Big Bang, and one of the characters set to appear is actually dead in the present. Now, CBS’ official logline for the episode - set to be titled “The VCR Illumination” has been released (via TV Line), giving fans a better idea of how things will work.

That’s all the information on the crossover available for now, but it provides an indication about how it’ll be pulled off. If the Young Sheldon characters - (Sheldon (Iain Armitage), his father George (Lance Barber), and his brother Georgie (Montana Jordan) - set to appear on The Big Bang Theory do so via a VHS tape, that would solve the timeline issues, and keep continuity intact. Unfortunately, it would also prevent any interaction between the two casts, which - considering Sheldon is sometimes visited by Professor Proton’s ghost in his dreams - could’ve theoretically been allowed to interact in some type of imaginary scenario.

Sheldon and Amy are still down about their theory being disproven, but a VHS tape from Sheldon’s past inspires him not to give up.

On a side note, TV Line’s report also revealed that Christine Baranski (star of CBS All Access series The Good Fight) will reprise her role as Leonard’s emotionally distant mother Beverly in the episode, although it remains to be seen how she’ll figure into the story. Perhaps Leonard and Penny will be off doing their own thing while Sheldon and Amy are inspired to pick themselves back up after disappointment, and that’s where Beverly will pop up. Baranski joins an array of season 12 guest stars, including Kathy Bates, Jerry O’Connell, Bill Nye, Bob Newhart, and Keith Carradine.

More: 20 Storylines Big Bang Theory Wants Everyone To Forget

The Big Bang Theory/Young Sheldon crossover episode “The VCR Illumination” airs December 6 on CBS.

Source: TV Line