The series follows Shelby and Cyd, who gain the power to leap forward and backward in time whenever they want - and sometimes when they don't. Now, the duo experience the twists and turns of friendship as they try to decide between fixing mistakes in the past or catching a glimpse of the future. While aspiring scientist Barry and his trusty assistant, Naldo, try to figure out how to replicate time travel for themselves, Cyd and Shelby use their newfound power to navigate high school, life and Shelby's mischievous twin brothers, Bret and Chet.
Best friends Shelby and Cyd gain the unpredictable power to travel back and forth in time when one of their friend Barry's science inventions goes awry. With their newfound power, the teen besties try to fix the mishaps that spoiled Shelby's plans to ask her crush Cameron out to the school dance.
Cyd and Shelby have trouble studying for an upcoming history test and try to jump ahead in time to steal the test questions; Barry and Naldo try to replicate time travel.
Cyd wants to plan a special thank you for the Marcus family; Shelby tries to help but everything leads to a misunderstanding and a kitchen disaster.
When Cyd and Shelby revisit their favorite memory from middle school, they're shocked to find that the moment wasn't the same as they remembered.
When Shelby's new lab partner, The Rob, can't stop being mean and annoying, the girls travel back in time to try and find out why he's such a jerk.
Cyd and Shelby go back to change the past so that Barry can meet his childhood science hero. However, when they return, they realize Barry and Naldo have changed as well and are now terrible rock musicians instead of aspiring scientists.
When the girls are assigned to do a report on the 1970s disco era, they decide to travel back and experience the 70s firsthand and land in the midst of turf battle between the disco and punk kids.
Cyd and Shelby discover a major clue to the future lab memory and it is somehow tied to Barry's science mentor Janet Smythe, who also employs Shelby's dad.
Cyd and Shelby use Barry's new invention to teleport themselves to New York City's Spooktacular in Central Park and get trapped in a haunted house with Riley and Lucas from "Girl Meets World."
When Cyd and Shelby go back to kindergarten to celebrate their friendship anniversary and relive the day they first met, they begin to change back to their five-year-old selves.
The girls go back in time to stop GDD CEO Janet Smythe from starting the corporation, when they learn she is behind the future lab. But their plan prevents other major events from happening in their lives, including them living together, and Barry and Marci falling for each other.
Trying to stop Janet's company, the girls alter other important things that happened in their lives. One of them is to get to know each other and the other is that Barry and Marci fall in love.
Things spin out of control when Cyd travels back to Christmas the year before to try and figure out the perfect gift for Shelby. Meanwhile, Barry and Naldo's Winter Wonderland experiment sparks an elf war with Bret and Chet leading the charge.
Shelby and Cyd try to use time travel to attend two events on the same night but the plan backfires when they both meet boys they like at each event!.
When Shelby's adventurous Grandma Rita comes to visit, the girls learn time travelers were responsible for setting up Shelby's grandparents and they jump to the 1950s to investigate.
When Diesel accidentally swallows a time travel tracker and disappears, Cyd and Shelby must track him down before he's lost forever.
When the girls discover their future-selves have asked to lose their time travel abilities, they leap to the future and see that evil Janet Smythe is somehow involved. Meanwhile, Barry learns Marci is planning to break up with him.
When Janet unexpectedly invites herself over to Shelby's for dinner, the girls use the opportunity to find out what she knows about time travel.
While Janet tries to uncover the secret behind time travel, the girls decide they need to take her down once and for all!
Cyd and Shelby discover a princess named Daisy from the 16th century has come through a time rift and she is in their school!
Bret and Chet are nervous about attending the 6th grade dance. With bad memories of their own 6th grade dance, Cyd and Shelby go back in time to get a second chance.
Since it looks like their time traveling princess may be here longer than expected, the girls decide to take Daisy on an official Shelby and Cyd "Epic Girls' Day" at the mall.
Complete episode guide for Best Friends Whenever with detailed information about every season and episode including air dates, summaries, ratings, and streaming availability in United States.
This episode guide is organized by seasons, making it easy to track your viewing progress or find specific episodes. Use the episode information to plan your binge-watching sessions or catch up on missed episodes.
When Barry is too busy to help Shelby build her new website, Shelby must take matters into her own hands! Meanwhile, Cyd and Naldo win a boat and try to hide the huge cruiser in the backyard.
When Cyd and Shelby go to a roller derby against Astrid's wishes, they find out that Shelby's mom has been keeping a secret.
Cyd turns into a menacing werewolf when she accidentally gets some of Barry's wolf serum on herself. Shelby then tries to figure out how to counteract the serum before the she-wolf destroys the school's Halloween carnival.
When Shelby and Barry compete against each other to have their latest innovations win at the Dax Fraggins Tech Pitch Fair, the aspiring scientist's ego causes him to be a jerk to fellow contestants and even his friends.
The time-traveling besties' friendship is in trouble when Shelby learns Cyd went to a concert without her and lied about it. Meanwhile, Bret and Chet try to earn their camping badges from the safety of their backyard.
Shelby and Cyd get their first jobs at a fudge kiosk at the mall, but the job isn't what Shelby thought it would be.
Daisy reveals she's engaged to a young man she's never met, so Cyd and Shelby travel to the 16th century to help her break off the engagement.
Shelby and Cyd are excited to plan the annual neighborhood Christmas party, which takes an unexpected turn when Daisy joins the festivities. Meanwhile, Barry plays Santa after the twins take the mall Santa captive.
Shelby gets trapped in the 16th century after trying to save Daisy from marriage, so the friends join forces to help rescue her.