And then there were fewer

Phineas, Ferb & the gang are invited to a party at a remote mansion. The guests discover that the event was orchestrated by the born-again Christian James Woods and his new girlfriend to their shock and the whole event is to make amends with each guest who he has wronged in his life. Things turn dark, however, when several guests including James Woods and his girlfriend start dying off inexplicably. Now, Phineas, Ferb & the gang must solve the mystery and find who killed them. However, when Phineas & Isabella was looking for the killer, they come face to face with the 2 killers......