In the Alias Season 2 finale, "" (Episode 22), the phrase "useful piece" refers to a critical component of a Rambaldi artifact .
The episode centers on a desperate race between the CIA and Arvin Sloane to assemble the final machine of Milo Rambaldi . Key events include:
: Sydney confirms Allison's identity when the double accepts a scoop of coffee ice cream—a flavor the real Francie famously hated .
: Sydney discovers that her best friend Francie has been murdered and replaced by a genetic double, Allison Doren .