When a well-off Hong Kong family move into a new home in Taiwan, impoverished handyman's son Wang Chi-Chiang convinces Shiao-Ming (Lin Hsiao Lan) and her bratty brother Shiao Tai their house is haunted. Sure enough a mysterious force compels all three kids to open a door hidden in the basement. Whereupon Tong-Tong, a little hopping vampire boy, leaps out of the tomb where he was imprisoned for three hundred years. As a thank you Tong-Tong transports Shiao-Ming and Chi-Chiang into a comic book (leaving Shiao Tai behind, presumably because the kid is an asshole) for a fun adventure. While Shiao-Ming and Chi-Chiang use their new-found magical powers to help rescue a princess held captive by a cannibal tribe, in the modern world Tong-Tong's vampire parents search for their son, causing all kinds of chaos.
A typically schizophrenic Hong Kong-Taiwanese kung fu fantasy-horror film for children, Haunted House Elf has no idea what it wants to be but provides sporadic fun. Star Lin Hsiao Lan was a staple of Taiwanese children's fantasies at the time: e.g. Kung Fu Wonderchild (1986), Magic of Spell (1988), Twelve Animals (1990), etc. Here she gets to play an actual girl for once instead of an unconvincing little boy. Although awkwardly cast as an adolescent she gets by with an endearingly childlike enthusiasm. Which is more than can be said for her young male co-stars, each of whom exemplify the curious problem HK children's films often have with crafting likable, sympathetic child characters.
To its credit Haunted House Elf establishes a complex psychological background for Wang Chi-Chiang: the child of a self-loathing alcoholic, who resents his mom for dying (?!) and copes with class-envy by lashing out or tormenting rich kids with tall tales about the living dead. Unfortunately the film fails to explore any of this promising material. At least Chi-Chiang's seems to learn a lesson from his jungle adventure (where, in typically reckless Hong Kong film fashion, the child actors are submerged in a real swamp, pelted with real snakes and tangle with a real tiger!) whereas Shiao Tai remains the same mouthy, abusive brat from start to finish. For some reason the first act also goes out of its way to establish some sexual tension between Chi-Chiang's handyman father Huang (Lin Chun-Han) and Shiao-Ming's mother even though the latter is clearly established as married. This subplot also goes nowhere making one wonder why the filmmakers even bothered.
With Haunted House Elf, Law's creative direction makes an otherwise slow-burning first act bearable, crafting an sense of supernatural dread although unusually for a HK horror-comedy-action film from this period the film lacks momentum. The plot starts out riffing on The Amityville Horror (1979) by way of Poltergeist (1982) then with the introduction of Tong-Tong joins the legions of child-friendly (uh, sort of) supernatural fare that took their cue from Mr. Vampire II (1986). Once the child heroes embark on their comic book jungle adventure things take a left-turn into Jumanji (1995) territory by way of Holy Virgin vs. the Evil Dead (1991)! Actor-director Wu Ma, the rapping Taoist wizard from A Chinese Ghost Story (1987) mugs shamelessly as the evil witch doctor who gets into a shape-shifting duel with the kids: morphing into a tiger, a poodle, a rat, Dracula, the Monkey King and... Jesus Christ. Whereupon the kids chase after him with a giant crucifix! As always good taste has no place in a HK-Taiwanese kiddie comedy.