Final answer:
Thyestes tried to devise some means to accomplish his evil purposes in fear of Atreus finding out. Atreus, upon finding out, plotted revenge against Thyestes.
Step-by-step explanation:
Thyestes, in fear of Atreus finding out, tried to devise some means to accomplish his evil purposes. Atreus, upon finding out, plotted revenge against Thyestes. He sent gifts to Thyestes as a sign of reconciliation, but in reality, it was part of his plan to seek revenge for the wrongdoings of Thyestes.