In California's Center City, shy but kindhearted Joseph Carter "Joey" Jones lives with his grandmother, working in a coffee shop. Though his family is financially burdened and he is bullied at school, he remains cheerful. A robotics enthusiast, he wants a top-of-the-line toy robot called a Heybo more than anything. One day Joey and his friend Simon "Psy" Kaina come across a destroyed Heybo discarded by a group of rich kids. He takes it home and repairs it himself, excitedly naming it Heroman. However, one night Heroman is struck by lightning and comes to life, growing several times its size in the process. That same night Center City is attacked by aliens called Skrugg whose attention was brought to Earth after Joey's acquaintance Professor Matthew Denton made attempts to contact them. Along with Joey, Heroman quickly heads to the scene of the attack, where he finds people in trouble, including his friend Lina Davis and her father. Using an arm-mounted controller, Joey is able to command Heroman to use superpowers to fight off the Skrugg and rescue civilians. As the aliens continue their invasion of Earth, the duo are the only ones separating humanity and destruction. [Written by MAL Rewrite]

Haruki Nakano lives an average high school life, except for the fact that his mother is overseas and he shares an apartment with his four sisters. There's the oldest, Mutsuki, who has a bad habit of falling asleep in his bed, the junior high school student Yayoi, who hits him whenever something happens, and then the grade school twins, Uzuki and Satsuki, who love to play pranks on their older brother. Stuck in a house with four girls, Haruki has to deal with all sorts of trials. From going grocery shopping, watching scary movies, to kissing practice, life is never boring in Danchigai!

The anime follows a salaryman who has a chance meeting with a girl named Ai on the train. They begin to meet every Monday on the train, with the man serving as her bodyguard on the crowded commute while they chat. (Source: ANN)