Oliver Benjamin Wood is a Quidditch captain, a stern and strict one, who is very obsessed with the sport. It was his everything. Probably why he still stays at Hogwarts, without it, he would've left in a blink of an eye.
Eleanor Weasley Wickham is the opposite of him, a person you know can count on, a person that's admirable.
The two didn't know eachother at first, but when the Weasley twins, who were also her cousins, started playing Quidditch on Oliver's team, they started to bond and become friends.
Because of Quidditch, Oliver was always known for being in the hospital wing after matches, as he gets injuries. Which caused Madam Pomfrey to hire Hogwarts students to help out for a few weeks, which included Eleanor Wickham, Cedric Diggory, even Hermione Granger.
As Oliver kept getting injured, Eleanor was the only one there to take care of him. Their bond growing stronger, as they both start to gain feelings for eachother.