Let's cut to the chase. Harry Kim wasn't an especially good character on "Star Trek: Voyager". He was just way too one dimensional and his actor, Garrett Wang, seemed hampered by this. He was either the really shy and relatively dull guy or he was saving the ship or he was doing something to almost destroy the ship! In many ways, he was this series' version of Wesley Crusher. A few episodes back he actually DID destroy the ship (only to magically un-destroy it thanks to temporal thingamabobs) and here he sure comes close to destroying a fragile alliance!
When the episode begins, Harry is having sex with some alien lady(?). This sort of stuff is against Starfleet regulations, as interspecies nookie has a proper series of channels that must be addressed first*. But the lovesick ensign acts more like a love- struck 14 year-old than a member of a professional crew. Naturally, when this dalliance comes to light, the Captain is furious, Harry apologizes and it all begins again. In the meantime, an underground movement among these aliens is discovered...and Mr. Kim is in the midst of it!
This is a moderately enjoyable episode but it didn't give Mr. Kim a great chance to expand as a character. It just reinforces him as an immature and somewhat unlikable sort of guy. Not terrible but it sure could have been better.
*These regulations they spout MUST have just been created (perhaps with Will Riker in mind). Riker routinely had sex with just about anything that moved--so saying that the captain and doctor need to approve on any Starfleet vessel before nookie can begin seemed odd to say the least!