North of Liberatia the Darantine Guard was soon ambushed by the tyranids, and the imperial force suffered heavy losses even before they reached their designated objectives. Worse was to follow as the Carcharadons raid soon faced heavier than anticipated resistance. The astartes put up a dogged defence as hordes of aliens poured out of the warren like terrain of northern Bastien, but by 1212.013M42 the northern mountains had to be abandoned, the region cordoned off and declared perdita.
In the Lacunis mountains the imperial operation progressed far more smoothly. The Apocalypse riders attacked the tyranids in the rough ground and soon stirred them into action, again rather more aggressively than they had bargained for. The Riders prooved a difficult prey for the aliens however, and managed to extract themselves from the mountains having inflicted serious damage on the tyranid horde. Then they ran east towards the plains of Liberatia, the creatures of Nemesis hard on their heels.
Once in the plains the Apocalpyse Riders retreated behind the Librian guard in a pre-planned operation. The Librians then waited behind their defence lines until the alien hordes appeared. Supported by heavy tanks, basilisk artillery and Baneblade super heavy tanks, the imperial line held even as the burrowing creatures of Nemesis appeared within their own ranks. The Librians had seen this before and were waiting for it, and as soon as the giant creatures erupted from the earth the Librian general sent in his reserves. Chimeras packed with plasma and melta weilding veterans made short work of the alien monsters, and once the larger beasts were felled, it was simply a case of mopping up. In Lacunis at least the tyranid threat had been eradicated.