The ones harassing Riko and her friends were "former" student council president Enomoto Yuiko (Eno), whose work was stolen by Maki, and her friend and student council treasurer Mizushima Sayori (Sayo). Declaring war on Riko and her friends, Eno and Sayo sneak into the student council room where they discover materials related to the love lab.
Meanwhile, Maki takes on all the responsibilities of the student council herself and collapses from the strain...
They're conducting a love 
lab in the student council?
¿Investigan el amor en 
el consejo estudiantil?
¿Investigan el amor en 
el consejo estudiantil?
Vous étudiez l’amour
 dans le conseil ?
Eles estão conduzindo um laboratório 
do amor no conselho estudantil.