Complex sentence: The 58th would find themselves courtmartialed for leaking information to the enemy leading to the defeat of the massive offensive planned by Earth forces in the final few episodes but their punishment is simply to be sent back to the front.
Split into simpler sentences: The 58th would find themselves courtmartialed for leaking information to the enemy, leading to the defeat of the massive offensive planned by Earth forces in the final few episodes. However, their punishment is simply to be sent back to the front.