Transformers: Prime Season 2 Episode 21 Alpha; Omega Episode Title:Alpha; Omega.Episode Description:Optimus Prime discovers that the Star Saber is embedded with a message from his former mentor Alpha Trion. In this message, Alpha Trion explains about four Iacon relics called the Omega Keys, which when brought together are able to make Cybertron inhabitable again. Meanwhile, Megatron opens the tomb of a deceased Prime on Cybertron, taking an arm and having it attached to him so he can use the Forge of Solus Prime to build a Dark Energon weapon strong enough to counter the Star Saber, the Dark Star Saber.