The episode itself begins with a suitably action-packed opening (as Amy and Rory's childhood friend and frequent troublemaker Mels hijacks the Doctor and TARDIS at gunpoint, leading to the TARDIS crashing into Hitler's office in 1938 Berlin -- thanks to Mels testing the Doctor's "temporal grace" story and revealing it to be simply a lie (thus answering that long-standing question)) that then gives way to something far more character-driven.
Steven Moffat must have taken a perverse pleasure in naming an episode something as provoking as "Let's Kill Hitler" (still to date the least Who-ish episode title ever -- although that may partly be because time and familiarity have robbed us of the impact of names like "Small Prophet, Quick Return") and then limiting Adolf Hitler's screentime to something like five minutes, before Rory locks him in a cupboard, not to be seen for the rest of the episode. Instead we focus on the character of Mels, who is accidentally shot and starts to regenerate -- revealing that she is in fact Melody Pond. "I named my daughter after her," Amy says about Mels. "You named your daughter... after your daughter," the Doctor replies. And so Mels regenerates into River Song -- but at this point River has been brainwashed into being a weapon designed to kill the Doctor; this is not the River that we know.
The Doctor fights to save Amy and Rory while the Teselecta and River look on. ("Let's Kill Hitler") ©BBC |
It's a surprisingly intimate episode, and despite the big title and the showy beginning, this is a story about how River came to be and what happened to Melody Pond after her regeneration in 1969.234 It doesn't really feel like a story in its own right so much as part of the continuing storyline of series 6, and that does harm it a bit -- it's not the sort of episode you're likely to watch out of sequence, like you can do with so many others. But it is filled with charm and honesty and care, and for that, if nothing else, it's worth your time.
234 Except that Mels is shown to be a little girl at the same time as Amy and Rory (i.e., 1996 and later), which leaves a rather large gap in which Mels either didn't age at all (which seems to be a thing she can do, based on River's comments about taking "the age down a little, just gradually" -- and yes, this is clearly meant to be an explanation for why she looks younger in "Silence of the Library" / "Forest of the Dead", but we can still use it) or she regenerated back into a little girl after having grown up for a while. Or possibly she did a bit of time travel. Regardless, it's a gap that's left unexplained.