In this episode of Trekking Through Compliance, we consider the episode Obsession, which aired on December 15, 1967, Star Date  3619.2.
On a planet, Kirk notices a sweet, honey-like odor that he recognizes. He orders the security guards to scan for choronium and fire at any gaseous cloud they encounter. Before they can do so, 2 are killed and one seriously injured. Kirk becomes obsessed with the destruction of the creature, which killed half the crew of the U.S.S. Farragut, which was  Kirk’s first deep-space assignment.
Scanners report that the creature is in a border state between matter and energy. The creature slows and heads for the Enterprise, and it enters the ship through the number 2 impulse vent, which had inadvertently been left open by Scott after performing maintenance. The creature then leaves the ship and heads away at warp speed, but Kirk has a hunch of where the creature is headed; it’s a home planet, where the creature is destroyed.

Compliance Takeaways:
1.     Sometimes, a CCO must make a stand and speak truth to power.
2.     How is a root cause analysis different than an investigation?
3.     Why you should train for crisis management.
Resources
Excruciatingly Detailed Plot Summary by Eric W. Weisstein
MissionLogPodcast.com
Memory Alpha