Where can I watch “Merlin” Season 5 Episode 12 online?

This page provides episode info and a legal-only guide. It does not host streams or downloads. Check official platforms and licensed services for availability in your region (US first).

Do I need to watch earlier episodes before “The Diamond of the Day (1)”?

Watching earlier episodes in season 5 helps you follow the plot and character arcs leading into this episode.

Watch Merlin Season 5 Episode 12 Online

“The Diamond of the Day (1)” — Watch "Merlin" Season 5 Episode 12 online in HD for free. Check streaming providers, cast, and episode details.

Dec 22, 2012 Season 5 Episode 12 43 min TV-PG

7.9 ★ ★ ★ ★ ★

11 votes

Merlin Season 5

← Back TV Series

Where can I watch "The Diamond of the Day (1)" online?

You can watch it through the button below, and it is free.

▶ Watch This Episode Now

Season 5 Episode 12 — Aired on Dec 22, 2012 • runs about 43 minutes.

Directed by Justin Molotnikov.

Written by Jake Michie.

Notable cast/guest names in this episode include Colin Morgan, Angel Coulby, Bradley James, Katie McGrath.

This page includes 4 official still(s) (when available) plus legal availability links.

Looking for “watch Merlin Season 5 Episode 12 online”? This is a legal-only guide with synopsis, stills, and navigation for this season.

Synopsis

High in the mountains, a great horde gathers; Morgana prepares for war with a vengeful Mordred at her side.

Merlin feels the weight of his destiny like never before as the ancient prophecies play out with terrifying accuracy. But before he can save his beloved Camelot, he must save himself. For it is not just the kingdom Morgana wishes to destroy – it is also Emrys.