An alternative series Futakoi Alternative (フタコイ オルタナティブ) by ufotable was produced where the anime series ran for 13 episodes from 7 April to 30 June 2005. The show features many of the characters from the original Futakoi. A manga adaptation of the show is illustrated by Kanao Araki.
Nozomu Futami returns to his childhood town where he moves in near a shrine which houses a legendary stone that was rumoured to have been the place where twin girls turned into birds. The stone is rumoured to be the cause of an abundance of twin girls who are born in the town and turn into birds because of their love for a man who couldn't choose between them. Shortly after Nozomu enters town he begins to run into the same problems as six pairs of twins fight for his love.
One day a set of twins, Sara and Sōju, showed up at the doorstep of Rentarō Futaba and his detective agency. They move in with him and work as secretaries for his agency.