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.

Ada Shore (Diane Hart) arrives at Skerryvore University in Scotland in search of her long-lost uncle Connell O’Grady (Joseph Tomelty), who was once a subversive Irish poet but is now working under an assumed name as a University porter. Ada is mistaken by Principal Archibald Asher (Patrick Barr) as his new secretary, and she goes along with the impersonation. Archibald and Ada fall in love, which incurs the disapproval of the puritanical Professor Hayman (Duncan Macrae).