hatched a plan

• schemedCrafted underhanded plans
• plottedSchemed or graphed
• conspiredSecretly planned wrongdoing together
• devisedPlanned or invented
• concoctedCreated by combining elements

mastermind · scheme · plot · conspiracy · devious · cunning · secret · whispered · shadows · blueprint · strategy · accomplice · clandestine · brewing · cooked up · dreamed up · nest · eggs