get wise (to someone or something)
To find out, become aware of, more fully understand, and/or no longer be deceived (by something or someone). I've been taking small supplies from the office for a long time, but I think the boss is getting wise. People are finally starting to get wise to the need for environmental protection.
get wise to
Also be wise to. See through the deception of; also, become aware of. For example, It took a while, but she finally got wise to Fred's lies, or I'm wise to the fact that her clothes come from a thrift shop. [Colloquial; mid-1800s]