THOU SHALT NOT SWEAR, with Lau Ching-wan, Chan Ming-chun, Michael Chow Man-kin, Eva Lai Yin-shan and K. K. Cheung. Directed by Chin Sing-wai. Category II. Showing on the Newport Circuit. THOU shalt not think this is a filler for the post-holiday slot. After a summer of swordplay and kung fu, this low-budget ghost thriller, which does not even have a guaranteed box office-filling star, comes as a welcome alternative and one that marks the return of a genre popular in the mid-1980s (most notably with Till Death Do We Part ). And it is surprisingly well made for what it cost - a low-risk horror film that should easily recoup from theatrical and video release. What is more, Thou Shalt Not Swear has been released during a timely season - in fact the only season - of the Chineseghost festival. The film is about seven neighbourhood kids - six girls and one boy - who swear to meet every year during the Chinese Halloween. Those who break the vow will pay with their lives. Years later, as grown-ups, they one by one die in mysterious circumstances until there are only two left: Chan Ming-chun and Eva Lai. Lau Ching-wan and Michael Chow play the buddy-b uddy cops investigating the case who get caught up in a cat-and-mouse chase with an evil spirit which hops from human host to human host. Chin, though never a stylist, deftly directs a film that is hauntingly atmospheric at times, but which also has an ample dose of conventional shock effects and a liberal sprinkling of laughs. The two lead actors may not have the screen presence of Tony Leung Chiu-wai and Jacky Cheung in Days of Being Dumb, but their chemistry works well on a different level - Lau's subtlety against Chow's hammy acting. Short on narrative flow but strong on Evil Dead -like shock tactics (without the cult horror hit's gore and obscenity), Thou Shalt Not Swear manages to elicit screams from jaded audiences, and that is more noise than most have made about the summer's tedious fare.