Epic, meticulously researched and ultimately disappointing, Martin Scorsese's bloody valentine to the birth of his beloved city is less than the sum of its parts. 1846, Lower Manhattan: New immigrants flock to the notorious Five Points slum, defined by the intersection of Mulberry, Cross, Worth, Orange and Little Water Streets, and wind up crowded into pestilent, lawless tenements. Colorfully named gangs — the Plug Uglies, the Bowery B'hoys, the Shirt Tails, the Daybreak Boys — fight for respect and control of the area's thriving criminal enterprises, with the bloodiest battles pitting the American-born Nativists, who despise the recent immigrants and take their orders from Bill "The Butcher" Cutting (Daniel Day-Lewis) against the predominantly Irish Dead Rabbits, led by Priest Vallon (Liam Neeson).The two tribes eventually go to war with knives, clubs and fists, fighting for the right to call themselves Americans; Bill the Butcher kills Vallon and declares the Dead Rabbits disbanded, their very name forbidden. Vallon's small son, Amsterdam, is handed off to a distant church school and emerges 16 years later a hard and embittered young man (Leonardo DiCaprio) with one ambition: To avenge his father's death. In the intervening years, Bill has risen from common thug to glad-handing crime lord with close ties to Tammany Hall's William "Boss" Tweed (Jim Broadbent), whose corrupt political machine runs New York. Amsterdam insinuates himself into Bill's brutal circle, gradually winning the older man's trust; in his rough way, Bill treats Amsterdam as the son he never had. Amsterdam also takes up with local girl Jenny Everdeane (Cameron Diaz), who shares some deep bond with Bill. Their stories are played out to their inevitable ends against the backdrop of the 1863 draft riots, four days of bloody mob violence that shook New York to its core. Scorsese began thinking about a film inspired by Herbert Asbury's 1928 Gangs of New York, an anecdotal account of 19th-century street crime, in the 1970s. But his mental energies appear to have been devoted entirely to the colorful and volatile period, leaving frequent collaborator Jay Cocks to devise a formulaic story and painfully cliched characters: the young man driven by vengeance; the brutal-yet-honorable gangster; the whore with, yes, a heart of gold. Day-Lewis alone manages to rise above the script: His Bill the Butcher is a caricature, but a brassy, vivid and thoroughly convincing one, bursting with the rude energy of a self-made monster. DiCaprio, a fine actor suffocating under his own delicate good looks, plays his role rather than inhabiting it, and Diaz — the least accomplished of the three — can't begin to make Jenny anything but a plot device. The less said about the closing song, U2's maudlin and self-important "The Hands That Built America," the better.