There are a lot of terms that mean to plan to to something bad, or likely bad, involving deceit; that seems to imply betrayal, but maybe it depends on how specific you are about what betrayal means. Otherwise, deceit, trick, con, etc., might work. The context in which some of these words are used might create the effect you intend.
A plan to steal by deception can be a con, a dwindle, etc.
something done by deceit or trickery in order to compromise or frame someone
The betrayal was actually twice as deep because it had all been a setup.
In The Deal's Secret Heir. Kat Cantrell. https://books.google.com/books?id=AHfACwAAQBAJ&pg=PA144&lpg=PA144&dq=it+had+all+been+a+setup
A plan made in secret by a group of people to do something illegal or harmful.
a secret plan or scheme to accomplish some purpose, especially a hostile, unlawful, or evil purpose:
a plot to overthrow the government.
Despite the definition' s use of group, one person can make a plot.
a plan or trick used for hiding your true intentions
Subterfuge is a trick or a dishonest way of getting what you want.
Most people can see right through that type of subterfuge.
the use of underhand machinations or deceitful stratagems.
The intrigue was therefore one for placing a son of the French king on the Spanish throne.
And, as in your user name, there is a sting! A sting usually, or perhaps always, involves a group of people acting together to trick someone out of money. There is a very famous movie from 1973 about a sting: https://g.co/kgs/uozqZD
us a carefully planned and complicated plan which deceives people so that criminals can steal something
A bank employee was involved in the sting in which $5 million was stolen.