If Today Was Your Last Day

Mia Lee is Caspar Lee's younger sister.
When Caspar moved to London, Mia was heartbroken. But they Skyped whenever they could, and it meant that Mia got more freedom, as Caspar liked to know who she was with and where she was going... All the time!
But when Mia moves in with Caspar and his roommate, Joe, does Mia find herself falling for Joe? And does Joe find himself falling for Mia? Do they tell Caspar?

"What would you do if today was your last day on earth?" Joe asked.
"Kiss you."