Couple of Mirrors Ending

Xu Youyi and Yan Wei try to carry on with normal life after the birth of the baby. However, mysterious white roses keep appearing in and around the photography studio. Yan Wei is clearly disturbed by them, but she doesn’t tell Xu Youyi anything.
One day, Yan Wei receives a note with two names written on it. She tells Xu Youyi she has to go out that night. Later, we see her on a rooftop dressed in her stealth gear, aiming her sniper rifle at a target. We hear her addressing Xu Youyi in a voiceover: ‘You’ve said goodbye to your past. I should say goodbye to mine too. Haven’t you always been curious about my past? I’ll tell you all about it when I come home.’ She shoots.
We then cut to a courtroom scene (which is very obviously the same footage as that used in previous episodes) where Yan Wei is on trial for murder. The judge finds her guilty, but because she turned herself in and pleaded guilty, she is given a comparatively light sentence of 15 years’ imprisonment.
We then see a series of ominous still images: Xu Youyi’s ex-boyfriend Xie Yifan lying dead with a bullet through his heart and a white rose next to him; Yan Wei as a teenager at the military training camp; Yan Wei on various battlefields with her comrades; signs on the front door of the studio saying that it’s shut by government order; the broken remains of Xu Youyi’s new typewriter; a photograph of Xu Youyi and the baby, with bloodstains on it.
Roll end credits.
***
Frequently Asked Questions
What is going on? The ending is very unclear!
Yes, it’s unclear. The prevailing theory on Weibo is that Yan Wei either is or was formerly a member of a secret organisation of assassins who use the white rose as a signal, and that she was trying to cut ties with them. But really no theory has been officially confirmed or endorsed, so feel free to make up your own.
Who did Yan Wei kill? Was it Xie Yifan?
Again, unclear. One possibility is that Yan Wei was instructed by her organisation to assassinate Xie Yifan. On the other hand, Xie Yifan had left for Beiping (aka Beijing) in the middle of Episode 12, while Yan Wei was still in Shanghai. So that reduces (but doesn’t eliminate) the likelihood that she did it.
What’s going to happen next?
Look, your guess is as good as mine. We probably won’t know unless and until there is a second season. In the meantime, please flood the AO3 tag with post-canon fic.
Will there be a second season?
Again, unclear. What we know from various Weibo posts by the main cast and crew is that they plan to make one. The executive producer Yu Zheng has apparently sent the concept for the second season to the lead actresses. But given the vagaries of Chinese television production, it’s anyone’s guess whether: (1) it will actually get made and (2) it will actually air. Just watch out for an announcement about whether they’ve started filming.
Can I pretend that the last few minutes of the episode never happened and that it ended with Xu Youyi and Yan Wei celebrating their child’s birthday?
Yes. Yes. Of course. Death of the author, no gods no masters etc. Have fun.