Angus had taken the supplies with him because he knew his own likelihood to just keep working once started at it. The winter had been hard on the riding trails. He rode them and repaired them, one spell at a time. The crater in the very back of the property had only gotten bigger and deeper. Part of it, he thought, was natural erosion. The rest of it was looking like they had been back. Digging. Looking. Angus put layer and layers of spells into place to try to fill up the hole, make it impenitrable. The distraction had worked for several months, but now it looked like they were trying to go off in every direction again, looking for the house. He destroyed every single tunnel and then filled up the hole.
It took massive amounts of his magic and his energy. Robert was always better and stronger at this stuff than Angus was. Angus could do it, but it wore him out. Before long, he was sitting under a tree, drinking the no longer cold water. He leaned against the tree, utterly exhausted. There was no way, though, that he was letting them get to main house. No matter what.
As he was sitting, resting, his eyes shut, someone suddenly cast a spell and he found himself standing, chained to the tree, his wand thrown away across the woods. And then he heard the crackle of flame and the heat of it. He looked up. They'd set the tree on fire. He looked ahead of him and saw a really bad phony looking death eater costume. They fired at him, stunning him. He fell limp, dazed, unable to free himself from the burning tree. He heard the figure apparate out, leaving him to be burned alive.