After the first engineer dies right off the bat, Billie is in charge of making sure that the ship is running properly. Even more responsibility falls on her hands when she finds out the captain isn’t actually a captain and that she’s the only one on the ship who actually knows what she is doing. Not only does she now have to do her job and the job of engineer one, she also has to keep the ship flying since the captain is a sham.
The problem is that no one listens to her and her work often goes unnoticed. She's also very straightforward and doesn't have much of a sense of humour, so she often goes unnoticed among the more over the top characters. The show is a comedy so the situations they get themselves into are rather ridiculous, but more often than not, she’s the one who saves the day. Billie’s work is underappreciated. Even though the captain isn’t a real captain, the passengers think he is. So because he is supposed to be the “man in charge”, he gets all the credit for the work of the women on the ship, especially Billie.