  A Lax system in three variables is presented, two equations of which form the
Lax pair of the stationary Davey-Stewartson II equation. With certain nonlinear
constraints, the full integrability condition of this Lax system contains the
hyperbolic Nizhnik-Novikov-Veselov equation and its standard Lax pair. The
Darboux transformation for the Davey-Stewartson II equation is used to solve
the hyperbolic Nizhnik-Novikov-Veselov equation. Using Darboux transformation,
global $n$-soliton solutions are obtained. It is proved that each $n$-soliton
solution approaches zero uniformly and exponentially at spatial infinity and is
asymptotic to $n^2$ lumps of peaks at temporal infinity.
