Things were looking pretty bleak for Daenerys and crew at the end of the episode before the second-to-last episode. Both Missandei and Rhaegal had their necks sliced, and the Dothraki and the majority of the Unsullied perished at the hands of the ice zombies. Dany's army approached King's Landing looking so decimated, that Euron could have blown them away.
It's a wild turn of events considering the past seven seasons of Dany's arc. As many people on Twitter noted, she blew a three dragon lead!