The Hero has accepted (or even jumped at) The Call, and is ready to embark upon his grand journey to defeat the Big Bad. Unfortunately, in his excitement, he's left his friends in the dust. Even more unfortunately, he's just discovered that he has Feet of Clay or that his powers are fueled by The Power of Friendship.
Feeling greatly humiliated and apologetic, he must now convince his friends to rejoin him in the fight. A simple apology won't cut it after the way he brushed them off. They're not coming back until he says "I Can't Do This By Myself"; only then will they rejoin him, and even then they often feign reluctance to drive the point home.
This is also said when an otherwise independent person tries to recruit people. The independent people are embarrassed to admit that they're unable to answer the call by themselves. They don't have the added guilt of having abandoned their friends because, well, they don't have friends — they've taken too much care in avoiding friendships before this. The person they'll be asking help from will be an acquaintance, a coworker, or, for maximum Emotional Torque, The Rival.
- In End of Evangelion, Shinji says this to Asuka when the burden of creating a new world falls on his shoulders. She refuses.
- Monkey D. Luffy from One Piece gets an entire speech dedicated to the fact he can't survive without his True Companions. A later arc also had Luffy alone making several off-hand comments wishing his crew was present to do what he could not.
Luffy: I don't know how to use a sword, Shark Face!!! I don't know how to navigate either!!! I can't cook!! And I can't tell lies!!Usopp: Hey.Luffy: I know I can't live without help from a lot of people!!!Arlong: Shah ha ha ha ha ha ha... what a clever boy you are to admit your own helplessness!!! What a burden it must be for your crew to have such an idiot for a captain. I don't know why they fought so desperately to save you. You lack the slightest shred of dignity or ability! What gives you the right to be the captain of a ship!!? Just what can you do!!?Luffy: I can beat you.
- In Sailor Moon, during the second episode of the Makaiju arc, Usagi is the only member of her team that had her memories restored and thus the only member of the Sailor Senshi with the ability to fight. Memories of watching her friends die one by one to fight for her leads her to try and fight the Cardian that episode entirely alone - even at the cost of possibly never having her friends back again. Luna ultimately disobeys her wishes when she sees Sailor Moon clearly outmatched by the Cardian and returns the rest of the team's memories so they can help her. Unlike other examples of this trope, the team immediately helps her after regaining their powers and memories again and don't even require an apology.
- In My Teen Romantic Comedy SNAFU, Hachiman initially tried to take on Iroha's request on his own given that he's directly responsible for her problems. However, he's unable to solve the problem and eventually turns to the rest of his club seeking help.
- In Maleficent, Diaval is frustrated that the title character doesn't invoke this trope, and instead tries to send him away when she needs him most, as she's knowingly walking into a trap. He imitates her voice and says "I can't do this without you, Diaval." Hilarious and heartwarming at the same time.
- In Justice League (2017), this is why Batman forms the League. The Earth has caught Darkseid's attention, and Superman is dead—sorta, necessitating a group of powerful Metahumans to do what none of them could do alone.
- Buffy the Vampire Slayer has one of these. Buffy does it to Giles after she saves him when he goes to kill Angelus, right after Jenny's death.
Buffy: Are you trying to get yourself killed??? *grabs onto him* I can't do this by myself!
- In the pilot of Supernatural, brothers Sam and Dean have been estranged for several years when Dean shows up to recruit Sam to help him find their dad. Sam is reluctant to join, but Dean insists he needs his brother.
Dean: I can't do this on my own.Sam: Yes, you can.Dean: Well, I don't want to.
- Red Hot Chili Peppers: "Snow ((Hey Oh))" from Stadium Arcadium
Come to decide that the things that I triedWhere in my life just to get high onWhen I sit alone, come get a little knownBut I need more than myself this time
- Foo Fighters ' "Learn to Fly", between second and third chorus: "Fly along with me, I can't quite make it alone..."
- Red 's "Pieces". "I tried so hard/Thought I could do this on my own/I've lost so much along the way..."
- U2 's "Sometimes You Can't Make It On Your Own".
- "Superman" by Lazlo Bane is best known for being the title music from Scrubs, which specifically uses the lyrical hook of "I can't do this all on my own 'cause I know I'm no Superman."
- The Mrs Hawking series: In part V: Mrs. Frost, when Mrs. Hawking asks Madam Malaika for help in defeating their common enemy.
- Inverted by sci-fi action game Iji - After Dan and Iji's family is killed by an alien invasion, Dan urges his sister to forget about family bonds and throw away her feelings so she can focus on the mission, but in the end, it is Iji's love for her brother and her memories of her dead sister that sustain her through her fight against the invasion. Dan realizes this later in the game and acknowledges that neither of them can do it by themselves.
- After the 5th case in Phoenix Wright: Ace Attorney, the player is called upon to show the prosecutor Edgeworth a piece of evidence from the case that neither he nor Phoenix Wright could have put together without the other's help. More of an "I couldn't do this by myself", but still...
- If you're enough of a jerk in Dragon Age: Origins, Alistair will call you out for what you're doing to the reputation of the Grey Wardens. But he still remains in your party, adding that he can't stop the Blight by himself.
- Dragon Age II: From the moment you meet him, Fenris will ask for your help using pretty much these exact words. Comes up in his later personal quests as well.
- Mass Effect 2 has Shepard saying this to the Illusive Man when told that s/he needs to stop the Collectors and that humanity is at war. Shepard replies "If this is a war, I'll need an army. Or a really good team."
- In Sonic Forces, the main theme song "Fist Bump" opens with the line "I can't do this alone, even though I am strong."
- Red vs. Blue:
- In Red vs. Blue: Reconstruction, Agent Washington repeatedly uses this phrase or some variant of it to convince the Red and Blue teams to join his fight against the Meta, so much so that it's parodied in the first Rooster Teeth Short, where a fake recording session of Washington's voice actor Shannon McCormick shows him saying this, along with several other satirical versions of Wash's frequent statements. None of them would consider Wash a "friend", though - they only join him because they each hope to get something for themselves out of the deal (except for Caboose, who always seems happy to help anyone - even if they don't want him to). In fact, Wash tries everything from pulling rank to outright bribery (though notably not asking nicely) to get the teams to cooperate.
- In Season 3, Tex also invokes this trope when she realizes she needs one of the "idiots" (the Reds and Blues) to carry a bomb for her, as she doesn't have the upper body strength needed in her current body.
- Spoofed in The Onion article: "Antidepressant Can't Believe It's Expected To Fix This Mess All On Its Own".