: Amy and Rory's childhood friend Mels is revealed to be their daughter, Melody Pond . After being shot by Hitler (who is promptly shoved into a cupboard), Mels regenerates for the first time on-screen, becoming the woman known as River Song .
: Brainwashed by the Silence, River poisons the Doctor with "Judas Tree" venom, which prevents regeneration. [S6E8] Let's Kill Hitler
: A shape-shifting justice robot crewed by miniaturized humans from the future arrives to punish Hitler. However, they shift their focus to River, identifying her as the "greatest war criminal in the universe" for her future role in killing the Doctor. : Amy and Rory's childhood friend Mels is
: It is revealed that the TARDIS itself taught River how to pilot it, which explains why she is often more proficient than the Doctor. : A shape-shifting justice robot crewed by miniaturized
: The Doctor gives River her iconic blue TARDIS-shaped diary , marking the beginning of their complicated, "backwards" timeline together.