Twelve symmetrically placed, unclued lights (one hyphened) appear in a form suggested by a word that may be linked to their original forms (all normal words). Their unchecked and mutually cross-checking letters together spell out CRIPPLING LINKMEN DINING IN.

Across

1    Bridges crossing American and Asian boats (7)

6    Spanish plateaux framed in rocky seam (7)

11    Addresses person arrested by western marine (6)

13    Smart new union member issued forth drinks (4-7)

18    Unemployed star in audition (4)

20    Regularly observed Neptunian volcano (4)

21    Raise studs on outskirts of Epsom, chief (6)

23    Band splits, going west (5)

24    Taught withdrawn girl about old coin (8)

27    Unexpectedly produce...