Enterprise is stopped by another colorful rotating shape

Kirk and company have to act out the OK Corral shootout as the Clanton gang. This seems like the most reasonable way an alien can teach Kirk a lesson, right?

There’s a girl that seems to like Chekov

Kirk tries to tell everyone that he’s a spaceman, but they just act like he’s joking. It actually gets annoying how many times they try to tell people who they are, only to be responded to by thinking it’s a joke

Kirk tries to reason with the Earps, but it doesn’t go so well

Chekov gets shot! We’re told he’s dead

Kirk tries to reason with the sheriff, but that also doesn’t go so well

Bones and Spock make a gas grenade. They decide to test it on Scotty, but it doesn’t work

Spock determines that since the gas grenade didn’t work, nothing is real, and nothing will hurt them as long as they believe it. He mind-melds with everyone so they share his certainty. I think Spock is taking it really hard that his gas grenade didn’t work. Either that or Scotty just didn’t believe it would work and that’s why it didn’t put him out?

At the shootout, the bullets just go right through them

They appear back in Enterprise and Chekov is back.

The alien was impressed that Kirk could have killed the Earps but he didn’t