In the season finale, the rebels must infiltrate the heart of the Imperial fleet to rescue Kanan. This leads to an epic battle between Kanan, Ezra, and the Inquisitor, and results in the destruction of Tarkin’s flagship. Consequently, Imperial security on Lothal is strengthened, making their missions even more difficult in the future. Hera calls in help, but so does the Empire.
Source: Star Wars.com