Once Peter brought Tom the Potters' Secret (and received his Mark) Tom just needed to finish up some errands until he was ready to attack them: Give the cup to Bellatrix (instruct her to watch it well for him), give the diary to Lucius (tell him that when given the signal he should arrange for it to be brought to Hogwarts by a student, and the result would be mayhem that would destabilize Dumbledore's position), get the sword (or some other artifact) from Snape. And perhaps wait for the auspicious night of All Hallows Eve.
( Read more... )
( Read more... )