“You’re out of your league”: Q Who (TNG) vs. Regeneration (Enterprise)

Humanity comes face to face with the dehumanizing nightmare of the Borg, for the first time … twice.

“We’ve got a long way to go”: Eye of the Needle (Voyager) vs. The Sound of Her Voice (DS9)

The crew of Voyager come to terms with being stranded in the Delta Quadrant, and the crew of Deep Space Nine “shouldn’t have to mourn alone”.

“I’d like my death to count for something”: Yesterday’s Enterprise (TNG) vs. Year of Hell (VOY)

In these two stand-out episodes, we take a trip into two darker timelines … and get a glimpse of the very different TV shows that The Next Generation and Voyager could have been.

“Our relationship has evolved”: Before and After (VOY) vs. Twilight (ENT)

Voyager and Enterprise explore aging and memory loss, in a couple of their best episodes.

“I Love Lucy is on tonight”: Little Green Men (DS9) vs. Carbon Creek (ENT)

We see Earth through the eyes of 3 Ferengi in the 40s, and 3 Vulcans in the 50s.

“I’m a doctor, not an historian”: The Trouble with Tribbles (TOS) vs. Trials and Tribble-ations (DS9)

The Original Series gives us a comedic classic, and Deep Space Nine pays tribble-ute with a comedic classic of its own.

“Is there a John Luck Pickurd here?”: Yesteryear (TAS) vs. Tapestry (TNG)

Young Spock learns that the needs of an injured pet outweigh the needs of its owner, and young Picard learns that getting stabbed through the heart can be good, actually.

“Right, but at the wrong time”: City on the Edge of Forever (TOS) vs. Past Tense (DS9)

Kirk and Spock come to some horrible realizations, in a timeless classic; Sisko and Bashir make some disturbing observations, and give us a timely warning.

“You people certainly have interesting problems”: Tomorrow is Yesterday (TOS) vs Future’s End (VOY)

Kirk and Janeway try to preserve the timeline – more or less – when they’re each thrown back to the 20th century.