my brother/best friend vs. my alpha/my mate

my name is Terra me and my twin brother have just been forced into rogue life after our pack was killed by an unknown rogue group. but things are soon to get interesting when we go to a former ally of our deceased father a former alpha. but when we reach there land we are attacked by scouters(werewolves who stand guard in search of rogue intruders) we are taken prisoner awaiting our fate of which only the alpha may bestow. when he arrives he is furious to find that his mate aka me is being treated so badly and then without asking sentences my brother to death because he believes him to be my former affair .................