Angus was born 27 August 1895 the son of William Sanford Plewis and Christina Abernethy, in Ryde Township, Muskoka, Ontario. The last name of the family was sometimes spelled "Plewes".

Angus' Ontario Birth Registration.

On March 17, 1916 he joined the Army in Moose Jaw, Saskatchewan and was asigned to 229 Overseas Battalion Canadian Expiditionary Force.

Angus' Attestation Paper.

Angus arrived back in Canada on 13 June 1919 on board SS Olympic through the Port of Halifax, Nova Scotia after departing from Southampton, England.