Rose Tyler (Doctor Who)
At the beginning of season 2, Rose and the Doctor travel "farther than we've ever gone before" to New New Earth.  There they meet the Face of Boe again and help defeat some cat-nurses.  Over the course of season two, we learn that Rose has a crush on the Doctor, a point that is made strongly in 2.03 (when she competes for the Doctor's affections with former companion, Sarah Jane Smith) and 2.04 (when the Doctor falls for Madame de Pompadour).  Toward the end of the season, the Doctor starts to return affection for Rose, ending in the finale where Rose is trapped in a parallel universe (that looks just like ours) with her mother, Jackie, Mickey, and her parallel-universe father, Peter Tyler.