niagara niagara ( r ) bob gosse's niagara niagara follows a blueprint not unlike a lot of young-lovers-on-the-road movies . 
wild marcy ( robin tunney ) and calm seth ( henry thomas ) meet cute , literally running into each other while shoplifting at a local store . 
a mere couple of scenes later , the two embark on a journey to toronto from their small , unnamed american town in pursuit of a rare doll that marcy desperately wants . 
along the way , true love inevitably blossoms . 
what sets niagara niagara apart , though , is that marcy is afflicted with tourette's syndrome , a neurological disorder that causes sudden muscle and vocal tics . 
tunney , displaying an acting range not hinted at in the teenage witch thriller the craft , delivers an astonishing performance that won her the best actress prize at last year's venice film festival . 
to term her work a tour-de-force is not to imply that she attacks the scenery ; tunney's effectiveness lies in her modulation and vulnerability , which makes her depiction of marcy's illness--which often causes her to act violently--that much more convincing and tragic . 
she and the nicely subtle thomas develop a sweetly innocent and beguilingly off-kilter chemistry . 
their journey hits a few rough spots creatively along the way , mostly the fault of writer matthew weiss . 
a detour involving a kindly widower ( michael parks ) who takes the couple in brings the story to a screeching halt , and the key character of a trigger-happy pharmacist ( stephen lang ) is highly unbelievable . 
but these missteps do not blunt the power of tunney's bravura turn , which carries niagara niagara to a level of poignance it would not have otherwise achieved . 
 ( opens march 20 ) 
 " i didn't know what to expect . 
it's like something you chase for so long , but then you don't know how to react when you get it . 
i still don't know how to react . " 
--michael jordan , on winning his first nba championship in 1991 . . . or , 
my thoughts after meeting him on november 21 , 1997