Yuuta Segawa has just started his freshman year of university. One day, his sister Yuri, who raised him after their parents died, asks him to take care of her daughters Hina, Sora and Miu while she and her husband go overseas on a business trip. Yuuta grudgingly accepts, but tragedy strikes when their plane goes missing and all passengers are presumed dead. In an effort to prevent the three girls from being split up, Yuuta goes against their family and takes them in, just as his sister took him in when he had no one else. Now the four find themselves in a new and peculiar situation: Yuuta must learn how to balance his new responsibilities—as the newest member of the Street Observation Research Society, a club for people watching, and also as a father figure—while Sora, Miu, and Hina come to terms with the loss of their parents. [Written by MAL Rewrite]

Shy and soft-spoken Fumi Manjoume and upfront and caring Akira Okudaira were best friends in elementary school, but this changed when Fumi and her family moved away. Years later, Fumi moves back to her hometown after being accepted at Matsuoka Girls’ High School. She finally reunites with Akira, who is going to attend Fujigatani Girls’ Academy. Despite their reunion, their relationship isn't the same as it was years ago. As soon as Fumi starts attending school, popular senior Yasuko Sugimoto takes notice of her and flatters her more than any other underclassmen. After running to Akira for help so many times before, Fumi must figure out who she is as a person instead of standing in someone else’s shadow. However, that doesn’t stop Akira from wanting her friendship with Fumi to be as it once was. Will the girls be able to conquer the high school stage of growing up before it pulls them apart? [Written by MAL Rewrite]

It seems that when Lum was born, a postal screwup resulted in a witchy friend of the family not getting an invitation to the celebration. The witch put a curse on Lum, that she would never be happy with her True Love. 

In the present, a new Amusement Park has been built in Tomobiki, and opening day finds the whole gang sampling its pleasures. At a magic show, however, Ataru gets turned into a large pink hippo-potamus, FOR REAL! 

When Lum attempts to track down the magician that transformed her Darling, things start to get very weird, very fast! 

(Source: AniDB)

After the termination of the incredibly popular virtual reality MMORPG "The World," a new version of the game—The World R:2—is brought online. On his first day in the game, newcomer Haseo thinks he has made some friends to quest with. However, as if mocking his sentiments, they kill his character just for fun. Luckily, he is saved by a mysterious, one-armed player named Ovan who offers to show him around The World. Alongside Ovan and his cleric friend Shino, Haseo enjoys a wonderful first year in the game. But this peaceful life is shattered when Shino's character is killed by a familiar figure notoriously known as Tri-Edge, whose victims have all fallen into comas in the real world. In a fit of rage, Haseo vows to find the elusive Tri-Edge and kill him. Taking place during Haseo's first year in The World, .hack//Roots explores the friendships Haseo built in the game before Tri-Edge ripped them away. [Written by MAL Rewrite]