Adds a 1h cool down on army return and -10% gains. Cast it, and your army return time will turn from say 16h to 16-17h, with armies returning home when you login within that span.
Purpose would be to add another thing aside from +/- hrs to make scheduling easier (avoid being chained army home since there's no phone reception on buss home from work). Activity should be rewarded of course, hence gains penalty.