Tenma is a reincarnation of Osaka.Cloud Cuckoo Lander, sucks at sports and sleeps in class, and don't tell me this scene doesn't remind you of her. She's a non-Chaste Hero Osaka with longer, more Expressive Hair (and Psychic Powers)!
Akira and Karasuma are enemy spies with Tenma and Yakumo as their targetAkira is a spy, sent to investigate Tenma and Yakumo, two sisters who live with supernatural prowees (i.e: Tenma's time telling pigtails and Yakumo's mind reading). However, she has an obsticale... Karasuma. An enemy who has an idea: keep Tenma intrested in him and foil Akira's plans. Not as concerned, Akira keeps an eye on him but has another issue: Kenji Harima. The man's heart poured for Tenma is an issue. One wrong move, and he could expose her skills. To prevent this, Akira uses Eri as bait (she has no clue) to distract Harima and stick to her mission. Along with her teammate Hanai, Akira focuses on Tenma while Hanai focuses on Yakumo. His problems being he's not as experinced and she can tell he's near. This proves an annoyance and hinders progress. During time, Akira discovers Harima's ability to communicate through animals and with Iori, animals are capable of telling better then humans and could warn Harima of Akira. To prevent this, Akira makes Eri's interference more frequent, hoping to take his mind off of Tenma. Itoko also serves a role, after discovering Harima's crush on Tenma, she aims to make Harima confess (from locking him out to a hellish life). That way, she can expose Akira, Hanai, and Karasuma. So far, Yagami is a battlefield of these three masterminds (hence the title 'School Rumble'). By the end, Karasuma managing to tell Tenma he "loves" her and Harima's possible future with Eri may be a warning to Akira and could eventually cause a worldwide catasrophe... Or maybe not as severe but something important.