Episode Title:
Six Minus Six.
Episode Description:
Caesar attempts to use a machine to restore Rex's lost memories, but when it goes awry, Six intervenes and his memories of the past six years are accidentally erased. As a result, Six reverts to his personality from those days as a ruthless, selfish mercenary. As Six resumes his prior mercenary work, Rex intervenes, trying to remind Six of the man he became. Six eventually comes around and agrees to return to Providence, out of an interest in returning to who he once was.