  We investigate Bar-Natan's characteristic two Khovanov link homology theory
studying both the filtered and bi-graded theories. The filtered theory is
computed explicitly and the bi-graded theory analysed by setting up a family of
spectral sequences. The E_2-pages can be described in terms of groups arising
from the action of a certain endomorphism on mod 2 Khovanov homology. Some
simple consequences are discussed.
