The top 10 a cappella groups from the United States and the United Kingdom face off at the Beacon Theatre in New York City.

While preparing for semifinals, Craig makes some dramatic changes to the Hexachords' set and not everyone is happy about it; the members of Sharp Attitude head out of town for a much needed girls' weekend.

The semifinals are held in Philadelphia; a singer performs a solo in memory of her mother and strives to not get too emotional; two teammates butt heads over how to lead their group.

Sound check doesn't go well for one group, and it shakes their confidence; a sneaky set change leads to a confrontation between two team members.

Two singers plot to bring peace to rival groups; alums share bizarre wisdom with a team; perfectionists wrestle with an unforeseen flaw in their set.

One team head to the spa prior to a competition, while their rivals try to repair new wounds; alumni arrive in Philadelphia to help their old group, who are working with a Broadway star; the Maryland crew make a challenging decision.

Choreography proves difficult for a team in Philadelphia; the search for a beatboxer continues in Massachusetts; one team deal with new recruits who possess bad attitudes.

In the second-season opener, a team search for a beatboxer to replace the one they lost to rivals; and two competing teams have a karaoke battle to size each other up before the season officially begins.