- For other uses, see Excalibur.
In 2268, the USS Yorktown (Constitution-class) had been assigned to transport Excalibur to a security station at Starbase 6 for evaluation and testing. A group of renegade Andorians attacked and crippled Yorktown in an effort to steal the weapon. A shuttlecraft fled with Excalibur aboard, but it was hit by an asteroid bombardment and crashed on Melvinna. The crew hid Excalibur from pursuing Andorians in a pool which contained particles of verilium and obsitrate, a combination which blocked sensors. Most of the shuttle’s crew were killed, but one survivor, Phyllida Gaines, and Spock were able to retrieve the weapon. It was safely delivered to Starbase 6. (TOS short story: "The Enchanted Pool")