"The Sound of Her Voice" is the 500th episode in the "Star Trek" franchise. So, after tons of "Star Trek", "Star Trek: The Next Generation", "Star Trek: Deep Space 9" and "Star Trek: Voyager" they've finally hit this huge milestone. Unfortunately, while a very good episode, it wasn't as resounding a success as the show a few seasons back created to commemorate the 30th anniversary of the series ("Trials and Tribble-ations", 5.6).
The show's main plot involves a long distance distress call. A ship's captain, Lisa Cusak, has begun sending distress calls to anyone who might respond. It seems that something odd about the atmosphere of some planet caused her ship to crash and the Defiant is many days away from rescuing her. There is a problem, however, because the crash site is a class L planet--with a thin atmosphere that necessitate Cusak using all her available oxygen...and then perhaps some. So, it's a race to the planet and the crew of the Defiant take time to talk with Cusak and keep her spirits high.
The other plot is ill-defined. For some reason that makes zero sense, Jake and Quark are working together on some smuggling. This plot DID end well, but otherwise is far inferior to the Cusak one in every way.
So is it any good? Yup. But for a 500th episode I guess I just expected more. Still, it is worth seeing.