Lifetime has greenlit “Beach Girls,” its first limited series, based on the bestselling Luanne Rice novel of the same name. The six-hour drama centers on the friendship that begins among three teen girls during their families’ annual summer vacations at the beach. Twenty years after their last meeting, one of the three mysteriously dies and the remaining two are reunited and forced to deal with unresolved issues. A director has not yet signed. Casting is under way, with production scheduled to begin next month in Canada.