The road to Heglig has no sign or post marking the border between northern and southern Sudan, where Sudan's new war began on Saturday. Instead, there is a sudden trail of rotting corpses leading steadily north. At its head stands a northern Sudanese military base, now captured and looted by the South. Inside, South Sudan's generals plan their next offensive, marking troop positions and movements in the sand with a curtain rod. Outside, South South Sudanese soldiers mix freely with their allies — officially denied, but now in open view — from the Darfuri rebel group, the Justice and Equality Movement (JEM). The men are wary. They glance at the sky to check for approaching northern warplanes, and dig shallow foxholes for protection against bombs. Suddenly a Sudanese jet screams overhead. The dry desert air erupts with the thud of an aerial bombardment. "We are under attack," yells Maj. Gen. Mangar Buong, the South Sudanese commander. And the soldiers scatter for cover.