Paleb is the pairing between Caleb Rivers and Paige McCullers. They became friends through the shared interest in stopping "A" and protecting their loved ones.
In "Misery Loves Company," Paige and Emily are having a nice lunch at the school, when she reveals to Emily she has agreed to go see a doctor about her panic attacks. It was revealed that she was the one, on the phone with Caleb. The pair decide to find A's new lair, to take Mona down.
In "Out of the Frying Pan, Into the Inferno," Hanna overhears Paige on the phone with Caleb telling him that they need to come up with a better plan because Caleb putting the brain in Mona's locker didn't help. She tells him that she's going to be there at 7 and Hanna decides to follow her.