The Efrafan's are spotted by a mouse who was saved by Hazel sometime before and therefore tells Hazel of the incoming enemy. Hazel makes an attempt to come to terms, suggesting that they work together rather than fight and also build a warren half way between them to make them all stronger and relieve the overcrowding in Efrafa. His offer is refused and countered with the demands that Bigwig, Blackavar, and the escaped does are waiting for them when they arrive on the Down or he'd tear the throats out of every buck in the warren.
Holed up inside the warren, the Efrafans must dig to reach the Watership rabbits. The Battle lasts all night as Woundwort and Bigwig stand off inside the warren while Hazel, Blackberry, and Dandelion run off with a plan to release, Bob, the fierce guard dog of Nuthanger Farm, and lead him to the Efrafans.
Bigwig guards a run that goes to a burrow containing the members of the Watership Down warren (save Fiver, who had to be left in the Honeycomb), including Clover and her litter and a pregnant Hyzenthlay. Digging a hole just large enough for himself, he hides until Woundwort passes by, attacking him and biting deep into the General's foreleg, injuring it so badly that Woundwort is forced to hobble on three legs. Despite this crippling blow, Woundwort puts up a ferocious fight against Bigwig, but ultimately succumbs to exhaustion and attempts to coax him out. Bigwig refuses, loyally stating that his Chief Rabbit told him to defend the run and he would until told otherwise. No one had guessed that Bigwig was not the Chief and this gives Woundwort's patrol pause as they suspect that a Chief Rabbit would be larger and stronger than Bigwig. Woundwort, wounded and exhausted, surfaces and tells Vervain to fight Bigwig now. Fiver, now awake from his premonition stupor, apologizes to Vervain for his death, scaring the latter back out into the open.
Dandelion and Blackberry return, and the dog finally reaches the warren and attacks the Efrafans outside, killing a few and chasing off the rest. However, Woundwort fearlessly stands his ground, leaping towards the dog. The fate of Woundwort himself is not exactly clear, as his body is never found, but he is never seen or heard from again by any rabbit, bird, or mouse near the down. Given that he was severely wounded and exhausted from his fight with Bigwig, as well as the size of the dog, it is highly unlikely that he survived.
As a result of this battle and his skill in returning to Efrafa with the patrol, Campion became the new Chief Rabbit of Efrafa, and Groundsel left to become the Chief Rabbit of a new warren called Vleflain, the very warren Hazel had proposed creating to Woundwort. And so ended the conflict between Efrafa and Watership Down.