This should be a fairly straightforward review.

It feels like a normal episode as Sakura captures the arrow card but things start getting strange when Sakura wins a trip to Hong Kong.
During her trip, she keeps getting dreams of being hypnotized into being killed.
Warned of this dangerous premonition by Syaoran's mother, Sakura has to be guarded only for her to get hypnotized and drawn into another dimension by the sorceress Madoushi who mistakes her power for Clow Reeds.
Madoushi blames Clow Reed for ruining her life and demands he come in exchange for Sakura's friends not aware that he died, so the remainder of the film is Sakura and co surviving Madoushi's onslaught.
This is just an extended episode and not a very good one, Madoushi can be menacing but ultimately one dimensional, it relies way too much on premonitions which were always the weakest parts of the franchise and the English dub messed up the narrative to try and give Madoushi sympathy which doesn't work.
Overall it's not worth the extra run time of a standard episode.
Final Verdict: It's a weak extended Cardcaptors episode made worst by the dub which I usually find bad anyway, Madoushi isn't a strong enough written villain to be in the franchise.