lie behind
Verb
Meaning
Used other than figuratively or idiomatically: see lie, behind.
To be the ultimate cause of.
What truly lies behind her sudden change of heart?
Examples
Through all this horror my cat stalked unperturbed. Once I saw him monstrously perched atop a mountain of bones, and wondered at the secrets that might lie behind his yellow eyes.
All the more honour to those who have with honest effort striven to pierce the veil and explore the mysteries which lie behind it.