Instead of falling off that cliff and going missing for five years and waking up in a river, Byleth falls down and somehow survives but is found by Imperial Troops while theyâre knocked out.
In my own play through of the Blue Lions Route I fought Ferdinand and he said that Edelgard has always been obsessed with Byleth, which means she is fixated on the professor even outside of having them as her homeroom teacher.Â
So Edelgard high-key has a âCapture If Possibleâ order. Sheâs not confident that they can, because the professor is strong and Edelgard doesnât doubt that theyâll have to die in order for her plans to come into fruition.Â
But, by some twist of fate, the Imperials find Byleth beneath the ruble, unconscious but alive. The Sword of the Creator is gone, but itâs easy for them to capture Byleth like this and transfer them to the Imperial Capital.Â
Edelgard is...ecstatic. Surely, this is proof that her destiny is right. One of the things she wanted most was the professor by her side and now fate has gifted her with them. She knows theyâll resist, try to get back to the Faerghus and the Blue Lions, but in time, once sheâs won, perhaps her teacher will see that her path is the best path.
They keep Byleth unconscious the whole way back to Ennbar, drugging them and making sure they donât wake. No one wants to fight them, even without a weapon. They could kill Byleth, perhaps, because Byleth is unarmed and outnumbered, but it would make the Emperor very unhappy, so itâs easier to keep them drugged until they have a prison set up.
Edelgard has the most elaborate, but comfortable, prison constructed. Thereâs only one door, a solid metal construction with multiple locks and bolts, and there are no windows. Itâs built in a high tower, with winding stair cases and halls that lead nowhere, a veritable maze just in case. The cell itself looks more like a guest room than a cell. It has a nice bed, more lavish than Bylethâs bed at Garreg Mach, and plenty of books to keep them from getting bored, and silk clothing (red, itâs all red, Edelgardâs colors). If you ignore the fact that Byleth wonât be allowed to leave when they wake up, you could almost forget theyâre a prisoner. She has only her most trusted friends (the Black Eagles) and servants enter this tower, and the fact Byleth is even being kept there is very hush hush for the most part.
Those Who Slither In The Dark try to get access to Byleth, but Edelgard isnât having any of it. Sheâll let them have Rhea, but they are NOT touching the professor. Itâs the cause of a lot of tension between the two factions.
Meanwhile Byleth is only being visited by the best healers in Edelgardâs employee/confidence. It takes a long time, but Byleth wakes up much earlier because of it.
Byleth...isnât happy to be here.
Byleth was the head of the Blue Lion House, and theyâre loyal to the Blue Lions and Dimitri, and the last they saw of Edelgard she was the Flame Emperor, who was involved with the ones who killed their father, and probably caused the Tragedy of Duscar, etc. Theyâre not happy at all. Theyâre worried sick, and anxious, because Dimitri wasnât looking so good before the battle, and they donât know where their students are, and they want to know whatâs going on.
They refuse to eat when the Black Eagle students bring them food. They sit there, silently glaring at them, demanding to know why theyâre here and what they want. Their former students assure them that theyâre not going to be hurt, that theyâre just here for their own safety until the war is over, but Byleth is in a less than gracious mood.
They donât attack, because theyâre a smart and theyâre aware that even if they got out of the room thereâs probably a whole slew of guards, and they donât know where they are. But refuse to eat, no matter how much the students beg them to. No amount of arguing, or insulting, or begging will get them to lay a hand on the food. It may seem like a stupid move, with their body growing weaker and weaker, but Byleth doesnât have very many other ways to fight back right now.
Eventually Edelgard herself comes to deliver food in a personal attempt to get Byleth to eat. They donât, at first, simply demanding to know whatâs going on, and where Rhea is, and Dimitri, and pretty much any news from the outside because no one has been telling them anything.
 Edelgard is harsh on them. She bargains information for their cooperation eating food. Sheâs brutally honest about her answers too, Rhea is captured, sheâs invading the rest of Fodlan, Dimitri hasnât been seen since he murdered his uncle (she says that specifically to make his less desirable than her, because why should the professor worry about a half mad man like that?), Claude is barely holding the alliance together, and sheâs confident in her victory.
Byleth refuses to eat in Edelgardâs presence again. They refuse to speak or even LOOK at Edelgard. At first, Edelgard is hurt and furious, arguing with them about why sheâs right, how much crests have hurt her, how opening up like she would have if they were her homeroom teacher. But itâs like yelling at a wall.
The truth is, Byleth does have sympathy for Edelgard, but they can never condone this war, and they canât stand her allies that killed their father. And even if they could somehow get past those two thing, in their heart they know theyâll always be haunted by Dimitriâs hurt, betrayed, face when that mask fell off.Â
Dimitri was the one that helped them learn how to be human, who came to comfort them with kind words and understanding when their father died, who slowly and honestly opened up about his past, who understood and included Byleth even when he was intimidated by their expressionless face, and they donât think theyâll ever quite let go of that loyalty.
So Byleth plans their escape.
It takes a long, long, time. But they start to eat more when certain students showed up with food, strategically stop asking certain students certain questions, start asking different ones to others. They memorize how long time passes between visits, only to find it erratic. They donât give up though. They learn to tell time in the guardâs footsteps that sound outside their door. They count how many are taken with each shift change, and how long they can count before the next shift, and what student will come in between those shifts in case there is any pattern. They count how many steps are taken before the sounds of footsteps disappear, and mentally map out the first floor from there.
Itâs just pure bad luck that Bernadetta happens to be the student visiting when Byleth enacts their escape plan. They knock her out and run for it, stealing any money and gold she might have on her (not much, just pocket change, because why would she need it if sheâs just going to feed her teacher?). They knock out one of the guards before he can make a noise, and take out the rest in sneak attacks before they can sound an alarm. Once the first floor is cleared, then comes the hard part.
They steal a guardâs armor and clothes, locking them in the room with a still knocked out Beradetta. Neither should wake for a while anyway, and Byleth locks them in the room and waits for the shift change. Once the next guard is there, they leave.
Itâs easier sneaking out of the city than they thought it would be, they just walk out in Imperial Armor.Â
The alarms arenât sounded until after Byleth has made it well outside the gates, from there itâs a mad dash. They might steal a horse. Luckily, they have an advantage, theyâre still in disguise, and theyâve already put distance between them and the search parties. So long as they donât mess this up, they can pretend theyâre searching if they get caught.
Itâs a stupid plan, kinda, because theyâll probably be looking for a lone guard, but itâs all theyâve got for now.Â
They donât stop moving at all, they have to put distance between themselves and Ennbar. At some point their horse flat out dies from exhaustion, and they shed their armor to gain more speed and distance.
Theyâre almost caught, but they jump into a rapid river and escape. No one is mad enough to jump after them.
Theyâre pulled out of the river what must feel like days later by a friendly civilian. From them they learn that theyâve been imprisoned for five years.
Five whole years in that damn room.
Somehow, by some twist of fate, this village just so happens to be just outside of Garreg Mach, and the Sword of the Creator washed up beside them. And Byleth canât help but think that thereâs some twisted sense of humor to fate.
Five years, almost to the day.
They wonder if their students have come, the Blue Lions they mean.They wonder if any are alive to keep their promise. Edelgard said no one had seen Dimitri in a long time, and with the war it seems almost silly that any of the others would remember their innocent promise.
Byleth goes to Garreg Mach anyway.