  We study the effect of a first-order phase transition in a confining $SU(N)$
dark sector with heavy dark quarks. The baryons of this sector are the dark
matter candidate. During the confinement phase transition the heavy quarks are
trapped inside isolated, contracting pockets of the deconfined phase, giving
rise to a second stage of annihilation that dramatically suppresses the dark
quark abundance. The surviving abundance is determined by the local accidental
asymmetry in each pocket. The correct dark matter abundance is obtained for
$\mathcal{O}(1-100)$ PeV dark quarks, above the usual unitarity bound.
