Section 11 of the Employment Act below may answer your question:
"11. Provision as to termination of contracts.
(1) A contract of service for a specified period of time or for the performance of a specified piece of work shall, unless otherwise terminated in accordance with this Part, terminate when the period of time for which such contract was made has expired or when the piece of work specified in such contract has been completed."
So, it ends when the period is up.