Rascal Does Not Dream of Logical Witch

Story :  "For the past three days, there have been two Rio Futabas."
After successfully breaking the time loop that he and Koga were trapped in, Sakuta's threshold for what qualifies as "odd" was higher than most. So seeing his friend Futaba in a net cafe late at night should have been downright unremarkable-if he wasn't already on the phone with another Futaba...The ever-logical second-year has a doppelgänger, and neither one can (or will) explain what's caused this sudden case of Adolescence Syndrome. With one of the Futabas staying at his place, Sakuta will have to work fast in order to solve this. After all, who knows what could happen if the two doppelgängers meet?"