Unclued lights (including one of two words and three pairs, 37 doing double duty) are characters in a play. A representation (fourteen letters) of its title appears in the completed grid and must be shaded.
 

Across

 
12    Short of money Rameau composed airs (5)
13    Understanding uni, long historic, admitting pupil teacher (6)
14    Conically roofed edifice on Australian street beside pub (9, two words)
17    Let rip! (4)
18    One of the poorest nabs a base prisoner (7)
19    Ancient city square ⅝ of vehicles avoided (7)
21    Old chandler has bit of a kip in maple tree (6)
23    Tango with aged pair from Perth (4)
24    State...