Ideas of Spangly Enhanced Assassins

The "Enhanced Woman" pops up randomly, on S.H.I.E.L.D and Hydra's radar. Both compete to get to her first.
Hydra wishes to use her as a weapon against, S.H.I.E.L.D. While S.H.I.E.L.D, wishes to protect her.
However, the "Enhanced Woman" is unaware of the two organizations. All she knows, is that someone is after her.

S.H.I.E.L.D sends in their best assassins, Barton and Grean to bring in the "Enhanced Woman".
The last place she's spotted? At a fancy party hosted by, Mr. Lane.
Mr. Lane is a rich billionaire, who may or may not be a "friendly." But he has been helping, keep the "Enhanced Woman" safe.

During this cat and mouse game, of bringing in the "Enhanced Woman". Two people go missing, Fury's team falls apart, and Hydra has a new assassin on their hands... but who is this assassin?