The Tenth Doctor (portrayed by the brilliant David Tennant) and Martha Jones (the gorgeous Freema Agyeman) first meet in the first episode of Series 3 of Doctor Who (2005- series), titled "Smith and Jones". The Doctor finds himself at the hospital in which Martha is a medical student, which suddenly disappears from Earth and lands on the Moon. Martha is the only one who isn't quite so freaked out about their situation, and as thus the Doctor enlists her help in order to discover the reason why they are there, and why the hospital is being investigated by the terrifying Judoon.
Ever since that day she became the Doctor's full-time companion (the Doctor himself stating she was "more than just a passenger"), appearing by his side throughout Series 3 and making reappearances in Series 4. It becomes clear from the outset that Martha has fallen love with the Doctor, but her advances towards him are rejected as it is supposed he is still pining over his love for previous companion Rose Tyler (Billie Piper).
Whilst at first Martha is driven by her intense unrequited love for the troubled Doctor, she eventually stands her own ground and becomes an instrumental leader and courageous woman later in the series. I enjoyed her interaction with him even though there were elements of tension and guilt (in the Doctor's perspective). There were definitely some moments where I wish her love was reciprocated so badly! It's one of those ships that were doomed from the start but that's why I loved them together.
Links:
• Martha profile
• Tenth Doctor profile
• Series 3