09e4cafc_tions___Crusader_Kings_II_Wiki__Requirement
[Ambition] Become Heir [Success Condition] Is Primary Heir [Success Effect] Gain 1.00 Intrigue [Requirement] 
Over 16 years old Not a prisoner Not primary heir Not incapable Liege is parent Primary heir has certain negative traits
Ambitions - Crusader Kings II Wiki
Requirement