Though the premise of the film is an intriguing one, it degenerates into a poorly executed satire of modern "issues" by the end.
Nic Cage is a professor who feels life has been unfair to him; his friend from college is getting a paper published based on research he claims is his (though he hasn't written anything down and is unable to prove his claim,) his wife is possibly having an affair with another man (though he has no proof, it is hinted at a few times,) and his daughter's see him as ineffectual and useless. He suddenly starts appearing in the dreams of other people, starting with his youngest daughter, an ex girlfriend then his students, before it spreads round the country. In the dreams he is inactive and watches as horrible things happen to people and this frustrates him. However this brings him a level of fame that he clearly revels in, to the detriment of his real life and relationships. Michael Cera runs a tech/advertising company that contact Nic to try and monetise his dream appearances, and it is here that Cage encounters a young woman who has had dreams of him in which he actively participates in sex with her. After a frankly horrendous attempt to recreate her dream, he suddenly becomes more active in the dreams of others, in a negative way.
This is where the film goes wrong for me, as rather than examine the phenomena and how his emotional state has altered the dreams of others, or the subtle and darkly humourous take on sudden unwarranted fame and it's effects on a person's life, the film becomes an examination of modern "cancel culture" and the attitudes of his young students to his sudden appearance in their nightmares. It flounders about, trying to make the point that cancelling people is bad because this one guy didn't actively do anything to get cancelled for, ignoring the many times people got "cancelled" for actively being horrible. He makes a self indulgent "apology" video and his family leave him.
It's a good, well shot film for the majority, but the heavy handed messages about cancel culture and big tech are too clunky and come too late in an otherwise interesting story to be anything other than a let down