Speaking to Entertainment Weekly, Andrew W. Marlowe explained that Castle (Nathan Fillion) and Beckett (Stana Katic) will get together on the show.
"Beckett and Castle finally realise their attraction to each other is too strong to deny," Marlowe said. "And decisions must be made by each of them."
Marlowe added that Castle will display "not-too-subtle jealousy" over Beckett's upcoming relationship with Tom Demming (Michael Trucco).
He also revealed that the romance will spark a "competition for Beckett's affection" as the season ends.
The season finale of Castle is scheduled to air on May 17 on ABC.