Star Wars: Clone Wars Season 7 Episode 1 - 4 Ups & 2 Downs
1. Down - Echo
The twist ending of the episode is that Echo, a clone from the series' legendary Rookies episode who has long been thought dead, is actually alive, somehow aiding the Separatists figure out the clones' strategies.
Echo's survival is not necessarily a bad thing. Though it is hard to believe he survived being next to an exploding transport ship back in Season 3's Counter Attack, Echo is a great character, and bringing him back as a Separatist ally (or prisoner) could lead to some heartbreaking tension later on.
However, his survival is so blatantly foreshadowed in the beginning of the episode when Rex looks at his picture and says he "has a feeling" that Echo survived because the battle droids are using old battle plans he and Echo drew up.
It's not surprising, then, to discover that Rex is right. When he and Tech ask who's been sending the Separatists' call signal, Echo's clone ID number is given.
If it weren't so obviously foreshadowed, this could have been a great plot twist, but paired with the scene in the beginning, it feels too, pun not intended, forced.