Celeste Girard (néeLoyal) is a pre-made adultSim from Mesa Flats, one of the neighborhoods shipped with The Sims Pet Stories. She is the cousin of Stephen Loyal and owns a cat named Diva. Celeste works as an Intern in the Medicinecareer track. While abroad, she met Damien Girard, who knew she was the one for him. After he came all the way to Mesa Flats and knocked on her door, he convinced her that the reverse was also true and the two have been inseparable ever since. They soon get engaged and plan their wedding at A Little Salmon Wedding Chapel. Celeste's bridesmaid is Tracy Kosmokos. At the beginning of the Midnight Masquerade story, Celeste marries Damien at the chapel but her cousin Stephen shows up late at the wedding, for which he apologizes. To make it up to Celeste, Stephen has to look after her cat Diva during her honeymoon. She does not appear again in the story, but does send cat toys and a scratching post for Diva with notes to Stephen.
At the end of the story, Celeste sends an email to Stephen saying that she and her husband are going on a cruise and that Stephen may keep Diva. Celeste and Damien are never seen again after the completion of the story and Stephen slowly loses his relationship with her. This might be a mistake of the developers, but could also have been intentional.
Since Diva's surname is Loyal when she moves in with Stephen, even though this move is not expected to be permanent, it seems likely that this is in fact the former surname and maiden name of her original owner, Celeste. This would mean that Celeste and Stephen's fathers are brothers, even though they don't exist in-game.
In her last email, Celeste writes that she and Damien went on a cruise. This might have accually been the Queen Solomon cruise ship of the Shipwrecked and Single story from The Sims Castaway Stories, which crashes and eventually sinks. If this were the case, Celeste and Damien must have been deceased, since they don't appear in the game's story as survivors. Which would explain why they never get back.