That Thing You Do!

In 1964, in Erie, Pennsylvania, aspiring jazz drummer Guy Patterson (Tom Everett Scott) is asked by Jimmy Mattingly (Johnathon Schaech) and Lenny Haise (Steve Zahn) to sit in with their band at an annual talent show, after their regular drummer breaks his arm trying to jump over a parking meter. The band, which also includes a bass player (Ethan Embry), adopts the name "The Oneders" (pronounced "wonders", but often mispronounced "oh-NEE-ders"). At the talent show, Guy launches into a faster tempo than intended for Jimmy's ballad, "That Thing You Do", and the band wins the competition. The Oneders' performance at the talent show earns them a paying gig at a local restaurant, where they begin to sell recordings of "That Thing You Do" and are noticed by talent promoter Phil Horace (Chris Ellis), whom they hire as their manager.
Horace achieves radio airplay for the song and books the band at a rock &amp; roll showcase concert in Pittsburgh, after which they are offered a contract by Play-Tone Records A&amp;R representative Mr. White (Hanks). White changes the band's name to "The Wonders" as they join a Midwestern Play-Tone tour, taking along Jimmy's girlfriend, Faye (Liv Tyler) as their official "costume mistress". During the tour, "That Thing You Do" garners national radio airplay and becomes a bona-fide hit. As the band's popularity soars, Jimmy grows frustrated that the group is not focused on creating more music, while the remainder of the band enjoys their time in the spotlight. All the while, Guy and Faye grow closer as friends. When the song enters the top ten on the Billboard charts, the band is taken off the tour and sent to Los Angeles.
Faye falls ill on the trip and is nursed by Guy. Jimmy is seemingly disinterested in her well-being, being preoccupied with trying to convince White to let the band record more of his original songs. After a publicity tour, the band is set to appear on The Hollywood Television Showcase, a nationally-televised live variety show. They begin to show signs of discord. Jimmy continues to vent frustration at White over the band's direction. The bass player (who was leaving to join the United States Marine Corps in a few weeks) goes to Disneyland with a group of Marines and never returns; he is replaced in the broadcast by a session bassist. During the performance, as the band is being visually introduced to the viewing audience, the caption "Careful girls, he's engaged!" appears under Jimmy's name. Jimmy becomes upset with Faye in the dressing room afterward, and says that he has no intention of marrying her. Heartbroken and weary with his arrogant personality and lack of devotion, Faye terminates their relationship.
The next day at a scheduled recording session, Lenny is missing, and Jimmy's grievances with White reach a boiling point and he quits the band. Guy is sorry to see the end of the band. White confronts him, and declares the band a one-hit wonder, but commends Guy for his smarts and integrity. After an impromptu jam session with his idol, jazz pianist Del Paxton (Bill Cobbs), Guy returns to the band's hotel, where he meets Faye and shares a long kiss with her. In an epilogue, it is revealed that Jimmy went back to Play-Tone and forms another band (The Heardsmen) and has a successful career as an artist and producer, Lenny becomes a casino manager, and the bass player earns a Purple Heart for injuries suffered at Khe Sanh. Guy and Faye start a family in Washington, where Guy teaches jazz composition at a music conservatory that he and Faye open.

Question: Who is missing from the scheduled recording session?
Answer: Lenny