At Balloch Moss mine in Scotland, water comes through a seam bringing a torrent of mud into the mine and flooding the pit shaft, resulting in 118 men being trapped, with nine missing. The only means by which the rescue team can bring the men out is through some old abandoned workings which are now full of gas and thus will cause delays in any rescue attempt.
| Actor | Role |
|---|---|
 John GregsonJohn Cameron | John Cameron |
| MMeg BuchananMargaret Wishart | Margaret Wishart |
| JJohn RaeDonald Sloan | Donald Sloan |
 Fulton MackayDan Wishart | Dan Wishart |
 Andrew KeirCharlie Ross | Charlie Ross |
| WWendy NoelJean Knox | Jean Knox |
 Russell WatersHughie Aitken | Hughie Aitken |
 Jameson ClarkDr. Andrew Kerr | Dr. Andrew Kerr |
| EEric WoodburnRab Elliott | Rab Elliott |
 Archie DuncanWalter Hardie | Walter Hardie |
 Jack StewartWillie Duncan | Willie Duncan |
 Anne ButchartBiddy Ross | Biddy Ross |
| MMac PictonJim Knox | Jim Knox |
| JJock McKayJock Woods | Jock Woods |
 Jean AndersonMrs. Sloan | Mrs. Sloan |
 John SingerTam Stewart | Tam Stewart |
| CChristopher PageGeorge | George |
| KKelty MacLeodMrs. Duncan | Mrs. Duncan |
 Hal OsmondSandy Mackenzie | Sandy Mackenzie |
| GGuthrie MasonJamie Knox | Jamie Knox |
| HHoward ConnellHughie's Manager | Hughie's Manager |
 Russell HunterPolice Sergeant | Police Sergeant |
 Sam KyddPorter | Porter |
 Jim BradyMiner (uncredited) | Miner (uncredited) |
| JJim MorrisMember of Rescue Team (uncredited) | Member of Rescue Team (uncredited) |