Divergence, ENT 4
For a two-part episode born, really, out of fan service (why do the Klingons have smooth foreheads in TOS?) this manages to be a lot of fun on its own terms. The moment when Captain Hernandez must bring the Columbia close enough so its Warp Bubble can envelop the Enterprise’s and Tucker can zip from one to another is really quite fun. I’ve often wondered about transwarp physics in relation to other objects in subspace, so it was great to see this visualized.
It’s also great to see an episode with Phlox as the hero. Pound for pound, Phlox is really the best thing about Enterprise.