Definitively the Neville Longbottom of Outlander, Fergus proved himself the kind of man brave enough to stand up to his friends in tonight's episode.
With Claire (Caitriona Balfe) taken hostage to heal the British sailors taken ill with Typhoid, Jamie (Sam Heughan) predictably went into hero mode to try and save her. That included trying to start a mutiny to take over the ship to catch up to Claire's captors, even though they had been promised that she'd be returned safely once everyone arrived in Jamaica. Naturally, Jamie ended up in the brig and tried to recruit Fergus to start another mutiny for him in order to save Claire. Even though Fergus pointed out that the plan was a logistical nightmare, Jamie guilt tripped Fergus by saying if he really knew what love was he'd move heaven and Earth for Marsali (Lauren Lyle).
It would have been very easy for Fergus to fall into this trap, risked his life to free Jamie and take over the ship. That's what his surrogate father wanted him to do, but Fergus proved exactly the kind of man he was when defied Jamie's orders and found a better way to go after Claire and save Jamie from a potential hanging. He didn't pit pocket the captain for the brig keys or start a mutiny, but used his powers of persuasion to get the captain to free Jamie of his own volition — preventing a mutiny and protecting Marsali from the sex-starved sailors that would have raped her if Jamie and Fergus were both thrown overboard.
Jamie has been Fergus' hero since the Scot saved the little boy from the brothel in France over 20 years ago. He has followed Jamie's example in almost every way, but in "Heaven and Earth," Fergus proved that he's his own man, capable of making his own decisions and thinking with a clear head when Jamie cannot. He luckily did not inherit Jamie's stubborn streak or else both of them would have been in grave danger. While Jamie preached of heroics and risking everything for the one you love, Fergus proved he was willing to do just that by risking Jamie's anger and ill favor in order to save Jamie's life. Fergus proved he understands that true love is doing what is best for someone, even if they don't agree on what that is.
Unbeknownst to Jamie or his maturing ward, Fergus' plan also saved Jamie from falling into the trap being set by the British sailors that want to turn him in for treason. If Jamie had successfully been able to take over the ship and catch up to Claire, he would have been arrested for the Jacobite pamphlets found in the print shop before it burned down. You can't move heaven and Earth for Claire if you're dead, bro. Thus, Fergus maturity and clear thinking actually saved Jamie twice, and thus he is the true hero for the week.
Outlander continues Sundays at 8/7c on Starz.