This episode was actually pretty exciting, because of the great personal risk that the characters were taking. The premise was a little far out there, but the action sequences were top notch.
In order to destroy a shipment of Force-enhancing kyber crystals to prevent their use by the Empire, Ezra infiltrates a Stormtrooper academy as a cadet--the "how" part of this is left unspoken--and he excels at the training to the point that he gains access to Agent Kallus' office. Here he attempts to steal a computer card containing secret codes so that Hera and Kanan can figure out where the kyber shipment will be flying; but before he can escape from the room, Ezra is confronted by another cadet, Zare Leonis, who at first seems to be an antagonist, but who turns out to be just as much under cover as Ezra. Leonis' sister disappeared several years earlier from the academy, and he's there to try to find out what happened to her. He warns Ezra about the security devices encoded on the disk which would have put the entire facility on lockdown had Ezra tried to get it out past the door.
Deciding to work together--"do we need an excuse to go against the Empire?"--the boys come up with a tactic by which Leonis distracts Kallus while Ezra levitates the disk out and into an air vent using his Force skills. A sidebar--I have yet to find a building with air ducts you can use as a secret network of passageways. But they're pretty common in movies.
Anyway, Ezra gets the data Kanan and Hera need, and they fly off to destroy the kyber shipment. Meanwhile Ezra goes against the plan to stay in the academy in order to protect two of the other boys who he had overheard were going to be taken away by the Inquisitor--that cadaverous dude from the last episode. All that Zeb and Sabine can do is wait for Ezra to come out of the facility.
He soon gets his chance. The first three boys to finish an obstacle course featuring flying platforms and live laser fire will be trained in a chicken-walker. Unfortunately Ezra is not one of the three, but Leonis and another talented cadet, Jai Kell, are. When Ezra creates a diversion with a small explosive device, Leonis takes out the adult walker pilot with a stun pistol, incapacitates the third boy (think "Draco Malfoy" and you get his position in this) and they head for the garage door, which starts to close because the base commander thinks they're under attack.
Ezra leaps aboard the walker, which the commander believes is an act of heroic bravery--"He's attacking it single-handedly!"--and as the machine passes under the door, it is hit by fire from outside and goes down--blocking the door open. Ezra and Jai jump into the speeder that Sabine and Zeb arrive in, but Leonis says he's staying at the academy in order to find his sister--and provides the "traitors" with some covering fire as they escape.
Leonis is commended by the base commander and the Inquisitor, and it's left dangling as to whether or not this is a good thing.
Meanwhile, Kanan and Hera attack the three Imperial freighters carrying the kyber crystal shipment. Kanan determines which ship is actually carrying the crystals, and decoys the TIE fighter squadron in the shuttlecraft whilst Hera attacks the transport, destroying the one carrying the crystals. A weird energy cloud erupts from the ship, and nearly swallows up the Ghost and the Phantom, but Kanan docks just in the nick of time and Hera escapes into lightspeed. See, Captain Solo--this is what a functioning hyperdrive looks like...
This episode was nearly non-stop action of the video game variety, but the storyline was pretty solid and it also further filled in details about what it's like to serve the Empire.
I apologise for posting this review late, but this site was acting flukey yesterday, giving me error messages and not responding properly.