Boston’s Jazz Composers Alliance Orchestra here offers eight pieces with thematic narratives, some with words, some not. In “November, 1938,” composer Darrell Katz revisits a section of “The Death of Simone Weil,” his six-movement setting of a text by poet Paula Tatarunis about the philosopher and mystic who died in 1943. Katz’s command of evocative orchestral harmony as well as a lovely melody (sung by JCAO vocalist Rebecca Shrimpton) convey longing and ultimate grace, with a bit of jazz swing. Similarly, in “Chazz’s Mingus Story,” Shrimpton and composer Warren Senders split a spoken-word fairy tale about a personal encounter with the great jazz bassist and composer — this time, personal turmoil is relieved by joyous, Mingus-like collective improvisation. Bob Pilkington’s “Aftermath” considers a natural disaster, moving from an eerie atonality to a final surge of regeneration in rhythm, harmony, and melody. Some pieces are just downright fun, like Norman Zocher’s “Wiggy Diggy” with its matching of pedal steel guitar, vibes, and a hard-rocking voice-and-horn riff. Or take Jim Hobbs’s positively Ellingtonian instrumental, “A Girl.” It is, Hobbs’ notes say, “A song about a girl.” Some stories are pretty simple after all.