Miles, Loretta, Leo and M.E.R.C. are preparing a special breakfast in bed for Phoebe because to day is Captain's Day. They make her toast with a picture of a rocket on it with a jar of jam and a vase of Meteor Flowers on the side. They deliver it on a tray and announce their plans to make this the best Captain's Day for Phoebe. Loretta has plotted a course to her favourite zero gravity spa and Miles has named a new Blastboard trick after her, which he calls the "Captain Curl". However he hasn't been able to master it yet. Just then, in spite of it being Phoebe's day off, Stella reports that the Tomorrowland Transit Authority is calling. The Callisto's report to the bridge where Admirals Watson and Crick inform them that a comet known as Liang is coming in their sector and will be visible by telescope on Planet Quatsa, much to Phoebe's delight. Phoebe's great ancestor discovered this comet over five hundred and thirty-six years ago and was named after her family name. Phoebe always hoped she would someday see it and now she has her chance. Admirals Watson and Crick instruct the Callistos to find out if the Liang Comet will have any effects when it passes Quasta and since it has never been so close to a planet before, there is no telling what it might cause is it makes it's pass by. Phoebe gladly accepts the mission and the Callistos soon take off to Quasta in the Star Jetter.
Since they do not have much time, the Callistos will have to move fast if they are to get to Quasta in time before the Liang Comet arrives. Leo suggests that the fastest way to get there is to pass a swirling passage of ice. Miles and Loretta are concerned because of how dangerous it looks but Phoebe assures them as long as everyone helps navigate they will be fine. They soon enter the zone passing and dodging huge icebergs. So far all is going well and are now halfway from their destination. Just then Loretta reports a huge asteroid made of ice in their path and since it's too big to go around, they decide to fly through one of the chasms, to the other side. Unfortunately they discover the chasm leads to a dead end. With all power to the forward shields, they blast through the icy walls and make it out on the other side. However, because that push used all the Star Jetter's power, the ship comes to a dead stop. When everyone thinks they will never get to Quasta now, Phoebe instructs M.E.R.C. to switch them to Connectic Mode and then turning off the gravity they start bouncing inside a projected grid that starts to recharge the Star Jetter's power with each bounce. With the whole family, full power is restored to the Star Jetter and arrive on Quasta just in time before the Liang Comet arrives.
While Phoebe sets up a Comet Lab, Miles goes off to practice that new move he wanted to show his mom. His first try ends with him failing off his Blastboard again but after the second try he succeeds in pulling off the Captain Curl. At the same time, Miles and M.E.R.C. meet a lot of Alien Rocks who have taken a liking to Miles' Blastboard. Miles gives them a ride on it and discovers they have quite a strong grip. Just then a huge strong wind passes through, nearly blowing away Phoebe's Comet Lab. Everyone tries to hold onto everything but the wind turns out to be too strong and all of Phoebe's equipment gets blown away, losing her chance to see the Liang Comet. However, with the help of the Rock Aliens, they manage to get all the equipment back and keep it well on the ground, just in time to monitor the passing Liang Comet. With the mission being a huge success, the Callistos decide to go back into space and give Phoebe a closer look at the Liang Comet, really making it the best Captain's Day ever.
- Cullen McCarthy as Miles Callisto
- Fiona Bishop as Loretta Callisto
- Olivia Munn as Phoebe Callisto
- Tom Kenny as Leo Callisto/Rock Alien
- Dee Bradley Baker as M.E.R.C./Rock Alien
- Danny Jacob as Admiral Watson/Rock Alien
- Diedrich Bader as Admiral Crick/Rock Alien
- Grey DeLisle as Stella/Rock Alien
- Captain's Day is a reference to Mother's Day
- According to Leo Callisto in this episode, the show is set five hundred and thirty-six years in the future, hinting the possible time period to be the 26th Century.
- It is revealed in this episode that Phoebe's maiden name is Liang.
- May 30, 2015 (Latin America)
- June 4, 2015 (Germany)
- June 6, 2015 (Spain, Portugal, Poland, Romania, Middle East, Africa)
- July 5, 2015 (Hungary)