The third season of Maria-sama ga Miteru. 
 
Summer has arrived at last, and with it comes the promise of summer break for the students of Lillian Girls’ Academy. Sachiko and Yumi retreat to the summer home of the Ogasawara family for a season of rest and relaxation, but their rosy trip soon sours when some old friends of Sachiko’s unexpectedly drop in. These wealthy snobs turn up their noses at Yumi and Sachiko’s relationship — and if Yumi isn’t careful, her blissful summer at Sachiko’s side could come to an abrupt and tearful end. 
 
(Source: Maiden Japan)

Maria Watches Over Us 3rd Season OVA