(2 of 19)

The Flash -- "Running to Stand Still" -- Image: FLA209A_0027b.jpg -- Pictured (L-R): Wentworth Miller as Leonard Snart, Mark Hamill as James Jesse/Trickster and Liam McIntyre as Mark Mardon-- Photo: Cate Cameron/The CW -- © 2015 The CW Network, LLC. All rights reserved.

(3 of 19)

The Flash -- "Running to Stand Still" -- Image: FLA209A_0038b.jpg -- Pictured: Wentworth Miller as Leonard Snart -- Photo: Cate Cameron/The CW -- © 2015 The CW Network, LLC. All rights reserved.

(4 of 19)

The Flash -- "Running to Stand Still" -- Image: FLA209A_0138b.jpg -- Pictured: Liam McIntyre as Mark Mardon -- Photo: Cate Cameron/The CW -- © 2015 The CW Network, LLC. All rights reserved.

(5 of 19)

The Flash -- "Running to Stand Still" -- Image: FLA209A_0144b.jpg -- Pictured: Liam McIntyre as Mark Mardon -- Photo: Cate Cameron/The CW -- © 2015 The CW Network, LLC. All rights reserved.

(6 of 19)

The Flash -- "Running to Stand Still" -- Image: FLA209A_0261b.jpg -- Pictured: Shantel VanSanten as Patty Spivot -- Photo: Cate Cameron/The CW -- © 2015 The CW Network, LLC. All rights reserved.

(7 of 19)

The Flash -- "Running to Stand Still" -- Image: FLA209A_0273b.jpg -- Pictured: Grant Gustin as The Flash -- Photo: Cate Cameron/The CW -- © 2015 The CW Network, LLC. All rights reserved.

(8 of 19)

The Flash -- "Running to Stand Still" -- Image: FLA209A_0288b.jpg -- Pictured (L-R): Shantel VanSanten as Patty Spivot and Grant Gustin as The Flash -- Photo: Cate Cameron/The CW -- © 2015 The CW Network, LLC. All rights reserved.

(9 of 19)

The Flash -- "Running to Stand Still" -- Image FLA209b_0014b.jpg -- Pictured (L-R): Wentworth Miller as Leonard Snart and Grant Gustin as Barry Allen -- Photo: Katie Yu/The CW -- © 2015 The CW Network, LLC. All rights reserved.

(10 of 19)

The Flash -- "Running to Stand Still" -- Image: FLA209b_0021b.jpg -- Pictured: Wentworth Miller as Leonard Snart -- Photo: Katie Yu/The CW -- © 2015 The CW Network, LLC. All rights reserved.

(11 of 19)

The Flash -- "Running to Stand Still" -- Image: FLA209b_0071b.jpg -- Pictured: Grant Gustin as Barry Allen -- Photo: Katie Yu/The CW -- © 2015 The CW Network, LLC. All rights reserved.

(12 of 19)

The Flash -- "Running to Stand Still" -- Image: FLA209b_0097b.jpg -- Pictured (L-R): Candice Patton as Iris West, Jesse L. Martin as Detective Joe West and Keiynan Lonsdale as Wally West -- Photo: Katie Yu/The CW -- © 2015 The CW Network, LLC. All rights reserved.

(13 of 19)

The Flash -- "Running to Stand Still" -- Image FLA209b_0100b.jpg -- Pictured: Candice Patton as Iris West -- Photo: Katie Yu/The CW -- © 2015 The CW Network, LLC. All rights reserved.

(14 of 19)

The Flash -- "Running to Stand Still" -- Image: FLA209b_0131b.jpg -- Pictured (L-R): Teddy Sears as Jay Garrick and Danielle Panabaker as Caitlin Snow -- Photo: Katie Yu/The CW -- © 2015 The CW Network, LLC. All rights reserved.

(15 of 19)

The Flash -- "Running to Stand Still" -- Image FLA209b_0146b.jpg -- Pictured (L-R): Shantel VanSanten as Patty Spivot and Grant Gustin as Barry Allen -- Photo: Katie Yu/The CW -- © 2015 The CW Network, LLC. All rights reserved.

(16 of 19)

The Flash -- "Running to Stand Still" -- Image: FLA209b_0173b.jpg -- Pictured: Jesse L. Martin as Detective Joe West -- Photo: Katie Yu/The CW -- © 2015 The CW Network, LLC. All rights reserved.

(17 of 19)

The Flash -- "Running to Stand Still" -- Image: FLA209b_0206b.jpg -- Pictured (L-R): Danielle Panabaker as Caitlin Snow and Teddy Sears as Jay Garrick -- Photo: Katie Yu/The CW -- © 2015 The CW Network, LLC. All rights reserved.

(18 of 19)

The Flash -- "Running to Stand Still" -- Image: FLA209b_0218b.jpg -- Pictured (L-R): Candice Patton as Iris West and Grant Gustin as Barry Allen -- Photo: Katie Yu/The CW -- © 2015 The CW Network, LLC. All rights reserved.

(19 of 19)

The Flash -- "Running to Stand Still" -- Image: FLA209b_0264b.jpg -- Pictured (L-R): Grant Gustin as Barry Allen and Candice Patton as Iris West -- Photo: Katie Yu/The CW -- © 2015 The CW Network, LLC. All rights reserved.