  We holographically compute an inter-boundary entanglement entropy in a
time-dependent two-sided black hole which was constructed in hep-th/0701108 by
applying time-dependent Janus deformation to BTZ black hole. The black hole
contains "causal shadow region" which is causally disconnected from both the
conformal boundaries. We find that the Janus deformation results in an earlier
phase transition between the extremal surfaces and that the phase transition
disappears when the causal shadow is sufficiently large.
