Can anyone give a detailed summary for it? Forgot the plot and can’t be bothered to read...

She transmigrated into the body of the villainess from the novel She had read in her past life. The story starts with her engagement annulment with the crown prince the reason being attempted murder on the saintess aka his lover and saintess. Upon discussions with the cp abt this situation she willingly leaves the capital to live in the northern territory thereafter she summons a demon and they gradually fell for each other