Battle at the Sandbox

The Battle at the Sandbox was the battle between HYDRA and S.H.I.E.L.D.. It was a part of the HYDRA Uprising.

Background
After his capture at the S.H.I.E.L.D. Academy for his illegal experiments with the Atmospheric Moisture Freezing Device, Donnie Gill discovered his ability to lower the temperature of objects upon touch. Gill was taken to the Sandbox and trained in harnessing his powers which then amplified. Eventually he was brainwashed into working for HYDRA.

In 2014, after being exposed and defeated by Captain America and his allies in the Battle at the Triskelion, the high command of HYDRA ordered all of their sleeper agents to purge all S.H.I.E.L.D. loyalists or non-HYDRA agents and capture all S.H.I.E.L.D. facilities for assuring their survival.

Battle
Agents from the Sandbox were revealed to be undercover HYDRA operatives and attacked the facility. HYDRA activated Donnie Gill's brainwashing and Gill used his freezing powers to eliminate many of the S.H.I.E.L.D. agents. Eventually HYDRA gained control of the facility.

Aftermath
After the battle, Donnie Gill temporarily broke his brainwashing and went on the run. Several months later, HYDRA and S.H.I.E.L.D. caught up with Gill in Casablanca, Morocco and he is killed by Skye.