Warning! SPOILERS for The Walking Dead season 10 premiere ahead.
The Whisperer War is about begin on The Walking Dead season 10, and it's all Carol's fault. The Whisperers were first introduced in season 9, and ever since, the threat of war with them has hung over each encounter. A nomadic group of people who wear the skins of the dead in order to hide among them, the Whisperers wield the walkers like a weapon. They are an opponent unlike any The Walking Dead's survivors have ever faced, led by a cruel woman, Alpha, who makes Negan appear almost tame by comparison.
Following the gruesome events of The Walking Dead season 9's trade fair - where several of the survivors are abducted, murdered, and have their heads put on pikes to mark the border with Whisperer territory - war seemed all but inevitable (and in fact, begins at this very point in The Walking Dead comics.) Instead, the survivors choose to honor the border so they can avoid another bloody conflict. Then, in the season 9 finale, that tenuous truce is almost broken when they must cross the border to find shelter from a winter storm. Luckily, the Whisperers didn't notice, but as of The Walking Dead season 10 premiere, avoiding a war is no longer an option.
In The Walking Dead season 10 premiere, "Lines We Cross", the Whisperers haven't been seen for months, but Alpha's border is respected all the same. That is, until a crashing satellite and its subsequent forest fire forces them to cross the border. The survivors manage to put out the fire without detection, but Daryl seizes on the opportunity the forest fire presents to sneak Carol - only recently returned from her stint as a sea captain - and himself to the quarry where the Whisperers' had previously penned their herd. He wants Carol to rethink her plans of running away again, insisting that he needs her to stay. Carol says she'll think on it, but as she lingers to look over the edge, Alpha enters the clearing below. She takes one look at Carol and the deed is done - Alpha knows their border has been crossed and The Whisperer War is on.
In the wake of Henry's murder and the end of her marriage to Ezekiel, Carol did what she always does - she ran away, isolating herself. Before it was a remote cabin on the outskirts of The Kingdom, this time it's life on a fishing boat for weeks at a time. Upon returning, Carol even asks Daryl to run away with her, wishing to pack up and leave everything behind. Daryl instead tries to convince Carol to stay, but in doing so, he thrusts her back into the center of the very conflict she was avoiding.
As The Walking Dead season 10 premiere repeatedly reminds us, both Alpha and Carol have be absent for some time. Alpha seemingly migrated with her Whisperers and the herd for the winter, while Carol sought solace at sea. Now they're back, and it was only a matter of time before these two women would be at odds again. Carol didn't have any intention of being the impetus behind The Whisperer War, but there's no turning back now.
The Walking Dead season 10 airs Sundays on AMC.