The Flash Season 3 Episode 21 : Cause and Effect

Latest The Flash Episodes

S09E04 : The Mask of the Red Death, Part One

S09E03 : Rogues of War

S09E02 : Hear No Evil

S09E01 : Wednesday Ever After

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Summary

Barry takes drastic measures to stop Savitar. Meanwhile, H.R. continues to push Tracy Brand to design the trap for Savitar and Killer Frost returns with an interesting proposal.

Episode Guide

Season 01

s011e01

season 01
episode 01

s011e02

Fastest Man Ali...

season 01
episode 02

s011e03

Things You Can'...

season 01
episode 03

s011e04

season 01
episode 04

s011e05

season 01
episode 05

s011e06

The Flash Is Bo...

season 01
episode 06

s011e07

season 01
episode 07

s011e08

Flash vs. Arrow...

season 01
episode 08

s011e09

The Man in the ...

season 01
episode 09

s011e10

Revenge of the ...

season 01
episode 10

s011e11

The Sound and t...

season 01
episode 11

s011e12

season 01
episode 12

s011e13

The Nuclear Man

season 01
episode 13

s011e14

season 01
episode 14

s011e15

season 01
episode 15

s011e16

season 01
episode 16

s011e17

season 01
episode 17

s011e18

All-Star Team U...

season 01
episode 18

s011e19

Who Is Harrison...

season 01
episode 19

s011e20

season 01
episode 20

s011e21

season 01
episode 21

s011e22

season 01
episode 22

s011e23

season 01
episode 23

Season 02

s021e01

The Man Who Sav...

season 02
episode 01

s021e02

Flash of Two Wo...

season 02
episode 02

s021e03

Family of Rogue...

season 02
episode 03

s021e04

The Fury of Fir...

season 02
episode 04

s021e05

The Darkness an...

season 02
episode 05

s021e06

season 02
episode 06

s021e07

Gorilla Warfare

season 02
episode 07

s021e08

Legends of Toda...

season 02
episode 08

s021e09

Running to Stan...

season 02
episode 09

s021e10

Potential Energ...

season 02
episode 10

s021e11

The Reverse-Fla...

season 02
episode 11

s021e12

season 02
episode 12

s021e13

Welcome to Eart...

season 02
episode 13

s021e14

Escape from Ear...

season 02
episode 14

s021e15

season 02
episode 15

s021e16

season 02
episode 16

s021e17

season 02
episode 17

s021e18

season 02
episode 18

s021e19

season 02
episode 19

s021e20

season 02
episode 20

s021e21

The Runaway Din...

season 02
episode 21

s021e22

season 02
episode 22

s021e23

The Race of His...

season 02
episode 23

Season 03

s031e01

season 03
episode 01

s031e02

season 03
episode 02

s031e03

season 03
episode 03

s031e04

season 03
episode 04

s031e05

season 03
episode 05

s031e06

season 03
episode 06

s031e07

season 03
episode 07

s031e08

season 03
episode 08

s031e09

season 03
episode 09

s031e10

Borrowing Probl...

season 03
episode 10

s031e11

season 03
episode 11

s031e12

season 03
episode 12

s031e13

Attack on Goril...

season 03
episode 13

s031e14

Attack on Centr...

season 03
episode 14

s031e15

The Wrath of Sa...

season 03
episode 15

s031e16

Into the Speed ...

season 03
episode 16

s031e17

season 03
episode 17

s031e18

season 03
episode 18

s031e19

The Once and Fu...

season 03
episode 19

s031e20

I Know Who You ...

season 03
episode 20

s031e21

Cause and Effec...

season 03
episode 21

s031e22

Infantino Stree...

season 03
episode 22

s031e23

season 03
episode 23

Season 04

s041e01

The Flash Rebor...

season 04
episode 01

s041e02

season 04
episode 02

s041e03

season 04
episode 03

s041e04

Elongated Journ...

season 04
episode 04

s041e05

Girls Night Out

season 04
episode 05

s041e06

When Harry Met ...

season 04
episode 06

s041e07

season 04
episode 07

s041e08

Crisis on Earth...

season 04
episode 08

s041e09

season 04
episode 09

s041e10

The Trial of Th...

season 04
episode 10

s041e11

The Elongated K...

season 04
episode 11

s041e12

Honey, I Shrunk...

season 04
episode 12

s041e13

season 04
episode 13

s041e14

season 04
episode 14

s041e15

Enter Flashtime

season 04
episode 15

s041e16

season 04
episode 16

s041e17

Null and Annoye...

season 04
episode 17

s041e18

season 04
episode 18

s041e19

season 04
episode 19

s041e20

Therefore She I...

season 04
episode 20

s041e21

Harry and the H...

season 04
episode 21

s041e22

season 04
episode 22

s041e23

We are the Flas...

season 04
episode 23

Season 05

s051e01

season 05
episode 01

s051e02

season 05
episode 02

s051e03

The Death of Vi...

season 05
episode 03

s051e04

season 05
episode 04

s051e05

season 05
episode 05

s051e06

The Icicle Come...

season 05
episode 06

s051e07

O Come, All Ye ...

season 05
episode 07

s051e08

What's Past is ...

season 05
episode 08

s051e09

Elseworlds, Par...

season 05
episode 09

s051e10

The Flash & The...

season 05
episode 10

s051e11

season 05
episode 11

s051e12

season 05
episode 12

s051e13

season 05
episode 13

s051e14

season 05
episode 14

s051e15

King Shark vs. ...

season 05
episode 15

s051e16

Failure is an O...

season 05
episode 16

s051e17

season 05
episode 17

s051e18

season 05
episode 18

s051e19

season 05
episode 19

s051e20

season 05
episode 20

s051e21

The Girl with t...

season 05
episode 21

s051e22

season 05
episode 22

Season 06

s061e01

season 06
episode 01

s061e02

A Flash of the ...

season 06
episode 02

s061e03

Dead Man Runnin...

season 06
episode 03

s061e04

There Will Be B...

season 06
episode 04

s061e05

Kiss Kiss Breac...

season 06
episode 05

s061e06

License to Elon...

season 06
episode 06

s061e07

The Last Tempta...

season 06
episode 07

s061e08

The Last Tempta...

season 06
episode 08

s061e09

Crisis on Infin...

season 06
episode 09

s061e10

season 06
episode 10

s061e11

Love is a Battl...

season 06
episode 11

s061e12

A Girl Named Su...

season 06
episode 12

s061e13

Grodd Friended ...

season 06
episode 13

s061e14

Death of the Sp...

season 06
episode 14

s061e15

The Exorcism of...

season 06
episode 15

s061e16

So Long and Goo...

season 06
episode 16

s061e17

season 06
episode 17

s061e18

season 06
episode 18

s061e19

Success Is Assu...

season 06
episode 19

Season 07

s071e01

All's Well That...

season 07
episode 01

s071e02

The Speed of Th...

season 07
episode 02

s071e03

season 07
episode 03

s071e04

Central City St...

season 07
episode 04

s071e05

season 07
episode 05

s071e06

The One with th...

season 07
episode 06

s071e07

season 07
episode 07

s071e08

The People v. K...

season 07
episode 08

s071e09

season 07
episode 09

s071e10

Family Matters,...

season 07
episode 10

s071e11

Family Matters,...

season 07
episode 11

s071e12

Good-Bye Vibrat...

season 07
episode 12

s071e13

season 07
episode 13

s071e14

season 07
episode 14

s071e15

Enemy at the Ga...

season 07
episode 15

s071e16

season 07
episode 16

s071e17

Heart of the Ma...

season 07
episode 17

s071e18

Heart of the Ma...

season 07
episode 18

Season 08

s081e01

Armageddon, Par...

season 08
episode 01

s081e02

Armageddon, Par...

season 08
episode 02

s081e03

Armageddon, Par...

season 08
episode 03

s081e04

Armageddon, Par...

season 08
episode 04

s081e05

Armageddon, Par...

season 08
episode 05

s081e06

Impulsive Exces...

season 08
episode 06

s081e07

season 08
episode 07

s081e08

The Fire Next T...

season 08
episode 08

s081e09

season 08
episode 09

s081e10

season 08
episode 10

s081e11

season 08
episode 11

s081e12

season 08
episode 12

s081e13

season 08
episode 13

s081e14

Funeral for a F...

season 08
episode 14

s081e15

Into the Still ...

season 08
episode 15

s081e16

The Curious Cas...

season 08
episode 16

s081e17

season 08
episode 17

s081e18

The Man in the ...

season 08
episode 18

s081e19

Negative, Part ...

season 08
episode 19

s081e20

Negative, Part ...

season 08
episode 20

Season 09

s091e01

Wednesday Ever ...

season 09
episode 01

s091e02

season 09
episode 02

s091e03

season 09
episode 03

s091e04

The Mask of the...

season 09
episode 04