I've recently been reading up about what makes a thriller a thriller. Amongst other things, a key marker is the constant escalation of the stakes, something which I'm not 100% sure my story has. I've gone through it, and tried to raise the stakes where I can, but I'm still not sure it follows the structure close enough. Here's a brief summary of the plot I have so far. The main character is a shapeshifter, and takes the form of the missing son of a rich family in hopes of claiming the inheritance when the very sickly father passes away. What at stake at this stage: just money. The main character tries to assimilate into normal life. He attends the missing son's school, meet's his friends, etc. What at stake: Prison, if he can't keep the act up. The missing boy's drug addicted sister returns from rehab. She knows something is fishy, and confronts him about it. He reveals the truth, which she is reluctant to believe, but agrees to go along with on the terms that he will help find out what actually happened to her brother. What's at stake: still prison, but it's more pressing now, because of the threat of the sister revealing the truth. A TV interview. They ask about how he went missing, etc. He realises that the whole world is watching him. If he is found out, it will be worse than prison. There will be chaos if the world finds out that shape shifter's exist. He could be killed or dissected. He eventually hacks the missing kid's computer, and finds a string of strange emails which imply that the kid was involved in some shady business. After an odd interaction with a kid at school, he begins to suspect that whatever the kid was involved with got him abducted. What's at stake: whoever the kid had a problem with, now has a problem with the main character. He has to find out who his enemies are or risk getting abducted again, or killed. I have an idea of how I want it to end but no exact plot points yet. I will say that there is a major reversal. Given this, would this be consider a thriller instead of a mystery?