Merlin_4x09 Here

"She was not herself, Arthur," Merlin whispered, stepping forward.

“Protect her, Merlin. The bracelet holds only part of her heart. The rest belongs to Arthur.” Merlin_4x09

The next morning, Arthur was banished to a life of sorrow, riding toward the borders of his kingdom. He looked at his hand, still feeling the coldness of the bracelet. But in the saddlebag, hidden beneath his armor, he found a small, white flower—a Valeriane , the flower he had once given to Gwen. "She was not herself, Arthur," Merlin whispered, stepping

Later that night, the pool of Nemhain glowed with a faint, unnatural light. Morgana stood on the bank, a triumphant smile on her face. Lancelot’s shade stood behind her, empty of his former nobility, a hollow puppet of her vengeful wishes 05:02. The rest belongs to Arthur

Highlights her success in using Lancelot, as mentioned in zahrawithaz's review.

The banquet hall was silent, filled only with the heavy, ringing sound of Arthur’s heart breaking. He held the bracelet, the enchanted token that had turned Gwen’s innocent love into a twisted betrayal, a plan Morgana had orchestrated using a reanimated Lancelot 05:17.

where Arthur finds out about Merlin's magic?