Z1 B65 56QPH B8LZ6 8LRV W88UH, B65 8LBZWPU 4B6SB1G RV L5 6GV5L CH6. 5ZVT Z1 B65 8LBZWPU 4B65LVG W88UH, 81 8LBBZR 5ZS7V 6QV56SL B65 SLL4, ZH6 ZABG6B 4BPDHP 65HE WSSG6B BHR. B65 8LBBZR 58BE RV L5 W88UH 481 4BZAHZ CH6. WP8ZV44B B65 SLL4 Z5Z7V 8BRL 481 1 WELZ614 BSVDHQ ZB6SVZ 8H Q8HZEBBR W88UH RV 481 Q8HG1SSW B65 PVD7B1V5H 8LBVC7S W1E1...

Z1 B65 56QPH B8LZ6 8LRV W88UH, B65 8LBZWPU 4B6SB1G RV L5 6GV5L CH6.
5ZVT Z1 B65 8LBZWPU 4B65LVG W88UH, 81 8LBBZR 5ZS7V 6QV56SL B65 SLL4, ZH6 ZABG6B 4BPDHP 65HE WSSG6B BHR.
B65 8LBBZR 58BE RV L5 W88UH 481 4BZAHZ CH6.
WP8ZV44B B65 SLL4 Z5Z7V 8BRL 481 1 WELZ614 BSVDHQ ZB6SVZ 8H Q8HZEBBR W88UH RV 481 Q8HG1SSW B65 PVD7B1V5H 8LBVC7S W1E1...

I noticed "1" on it's own and assumed it was A, so 1=A.
Then I did a frequency count and the most common character is B, so I assumed that to be E, so B=E.
I noticed there was some repeating words, most frequently "W88UH", so the mapping has to be 1-to-1.

_A E__ _____ E____ ____ _____, E__ __E____ _E___A_ __ __ _____ ___.
Z1 B65 56QPH B8LZ6 8LRV W88UH, B65 8LBZWPU 4B6SB1G RV L5 6GV5L CH6.

____ _A E__ __E____ _E_____ _____, _A __EE__ _____ _______ E__ ____, ___ __E__E _E____ ____ _____E E__.
5ZVT Z1 B65 8LBZWPU 4B65LVG W88UH, 81 8LBBZR 5ZS7V 6QV56SL B65 SLL4, ZH6 ZABG6B 4BPDHP 65HE WSSG6B BHR.

E__ __EE__ __E_ __ __ _____ __A _E____ ___.
B65 8LBBZR 58BE RV L5 W88UH 481 4BZAHZ CH6.

_______E E__ ____ _____ _E__ __A A _____A_ E_____ _E____ __ _____EE_ _____ __ __A ____A___ E__ ____EA___ __E____ _A_A...
WP8ZV44B B65 SLL4 Z5Z7V 8BRL 481 1 WELZ614 BSVDHQ ZB6SVZ 8H Q8HZEBBR W88UH RV 481 Q8HG1SSW B65 PVD7B1V5H 8LBVC7S W1E1...

I noticed "B65" was it's own word very commonly, and the most common triplet is "THE", but this word starts with an E, so I used a Crossword solver on the pattern "E??" and nothing that common came up.
I then thought - maybe it is reversed - which would explain the E at the start, so I reversed each of the individual words and made the now "56B" = "THE", so 5=T and 6=H.

A_ THE ___HT H___E ____ _____, THE ____E__ _A__HE_ __ T_ _T__H H__.
1Z 56B HPQ65 6ZL8B VRL8 HU88W, 56B UPWZBL8 G1BS6B4 VR 5L L5VG6 6HC.

____ A_ THE ____E__ ___THE_ _____, A_ __EE__ ____T __H___H THE ____, H__ EH_E__ ____E_ __TH EH____ __E.
TVZ5 1Z 56B UPWZBL8 GVL56B4 HU88W, 18 RZBBL8 V7SZ5 LS65VQ6 56B 4LLS, 6HZ B6GBAZ PHDPB4 EH56 B6GSSW RHB.

THE __EE__ _E_T __ T_ _____ A__ ____E_ H__.
56B RZBBL8 EB85 VR 5L HU88W 184 ZHAZB4 6HC.

E_______ THE ____ ___T_ __E_ A__ A _AH____ _____E ___HE_ __ _EE_____ _____ __ A__ ___A____ THE _T_AE____ ____E__ A_A_...
B44VZ8PW 56B 4LLS V7Z5Z LRB8 184 1 416ZLEW QHDVSB ZVS6BZ H8 RBBEZH8Q HU88W VR 184 WSS1GH8Q 56B H5V1B7DVP S7CVBL8 1E1W...

It was starting to come together, I took pot-shots at some more words - "1Z" has to be "A_" and the common two letter words starting with A are; As, An, Am and the only one that fit grammatically is AS, so Z=S.
After that there was a "H_S" and the common words to fit that are His and Has, and the A is already sued so I subbed in H=I.
This left me with an "A__" which appears a few time; I thought either And, Are, All, Any - The E is taken, it isn't a repeated letter and Any is a little infrequent so I went with And, so 8=N and 4=D.
There is also now a "T_", which could be from a frequent word list; To, so I guessed L=O.
Lastly I have "HI_" which could be His or Him, since the S is taken I went with Him, so C=M.

AS THE I__HT HSONE __ON I_NN_, THE ___SE_N _A__HED __ TO OT__H HIM.
1Z 56B HPQ65 6ZL8B VRL8 HU88W, 56B UPWZBL8 G1BS6B4 VR 5L L5VG6 6HC.

__S_ AS THE ___SE_N __OTHED I_NN_, A_ _SEEON ___ST O_H___H THE DOO_, HIS EH_E_S _I__ED _ITH EH____ _IE.
TVZ5 1Z 56B UPWZBL8 GVL56B4 HU88W, 18 RZBBL8 V7SZ5 LS65VQ6 56B 4LLS, 6HZ B6GBAZ PHDPB4 EH56 B6GSSW RHB.

THE _SEE_N _ENT __ TO I_NN_ A__ SI__E_ HIM.
56B RZBBL8 EB85 VR 5L HU88W 184 ZHAZB4 6HC.

EDD_SN__ THE DOO_ ___TS __EN AN_ A DAHSO__ _I___E S__HE_ IN _EE_SIN_ I_NN_ __ AND ___A_IN_ THE IT_AE____ __M_E_N A_A_...
B44VZ8PW 56B 4LLS V7Z5Z LRB8 184 1 416ZLEW QHDVSB ZVS6BZ H8 RBBEZH8Q HU88W VR 184 WSS1GH8Q 56B H5V1B7DVP S7CVBL8 1E1W...

Some of the longer word didn't make sense now, but I knew from the repeated words that it is 1-to-1, the smaller words made sense still though - so I tried to crack all of the 4 letter or smaller words since those were still english.
I had "DOO_", I thought Door, but I checked on a Crossword Solver and it gave me Doom as well, but M is taken so I went with Door, so S=R.
I realised I had missed a few gaps, so I went back and put those all in and the letters I have left to solve are P, Q, V, R, U, W, G, T, 7, A, D, E,

AS THE I__HT HSONE __ON I_NN_, THE ___SE_N _AERHED __ TO OT__H HIM.
1Z 56B HPQ65 6ZL8B VRL8 HU88W, 56B UPWZBL8 G1BS6B4 VR 5L L5VG6 6HC.

__ST AS THE ___SEON __OTHED I_NN_, AN _SEEON __RST ORHT__H THE DOOR, HIS EH_E_S _I__ED _ITH EH_RR_ _IE.
TVZ5 1Z 56B UPWZBL8 GVL56B4 HU88W, 18 RZBBL8 V7SZ5 LS65VQ6 56B 4LLS, 6HZ B6GBAZ PHDPB4 EH56 B6GSSW RHB.

THE _SEEON _ENT __ TO I_NN_ AND SI__ED HIM.
56B RZBBL8 EB85 VR 5L HU88W 184 ZHAZB4 6HC.

EDD_SN__ THE DOOR __STS O_EN AND A DAHSO__ _I__RE S_RHES IN _EE_SIN_ I_NN_ __ AND _RRA_IN_ THE IT_AE____ R_M_EON A_A_...
B44VZ8PW 56B 4LLS V7Z5Z LRB8 184 1 416ZLEW QHDVSB ZVS6BZ H8 RBBEZH8Q HU88W VR 184 WSS1GH8Q 56B H5V1B7DVP S7CVBL8 1E1W...

The last word had a unique pattern, so I ran that through a crossword pattern solver and got; Alas, Asap, Away, Adam, Ajar. But a lot of those letters were used and the only word containing all fresh letters was Away which also gives With and Went in some of the other spots, so E=W, W=Y.
The word denoted by "VR" is annoying me since it is a small 2 letter word repeated and it has no letters unlocked - so I consulted the common two letter word page again; of, to, in, it, is, be, as, at, so, we, he, by, or, on, do, if, me, my, up, an, go, no, us, am - but with a lot of those letters taken the only word left was Up, so I checked that in, so V=U and R=P.
The last short word I have is "_UST" - back to the crossword solver and I get; Bust, Dust, Gust, Must, Just, Lust - Eliminating the ones I can't use I get Bust, Gust, Just, Lust - But taking context into account "[word] as the ..." the word I went with was Just, so T=J.
The letters I have left to solve are P, Q, U, G, 7, A, D

AS THE I__HT HSONE UPON I_NNY, THE __YSEON _AERHED UP TO OTU_H HIM.
1Z 56B HPQ65 6ZL8B VRL8 HU88W, 56B UPWZBL8 G1BS6B4 VR 5L L5VG6 6HC.

JUST AS THE __YSEON _UOTHED I_NNY, AN USEEON U_RST ORHTU_H THE DOOR, HIS EH_E_S _I__ED WITH EH_RRY PIE.
TVZ5 1Z 56B UPWZBL8 GVL56B4 HU88W, 18 RZBBL8 V7SZ5 LS65VQ6 56B 4LLS, 6HZ B6GBAZ PHDPB4 EH56 B6GSSW RHB.

THE USEEON WENT UP TO I_NNY AND SI__ED HIM.
56B RZBBL8 EB85 VR 5L HU88W 184 ZHAZB4 6HC.

EDDUSN_Y THE DOOR U_STS OPEN AND A DAHSOWY _I_URE SURHES IN PEEWSIN_ I_NNY UP AND YRRA_IN_ THE ITUAE____ R_MUEON AWAY...
B44VZ8PW 56B 4LLS V7Z5Z LRB8 184 1 416ZLEW QHDVSB ZVS6BZ H8 RBBEZH8Q HU88W VR 184 WSS1GH8Q 56B H5V1B7DVP S7CVBL8 1E1W...

This is why I hadn't solved it faster, I sat on this step for a long time.
So after some time away doing assignments I cam back and listed all of the longer words into two columns; fully solved and partially solved.

__YSEON
_UOTHED
I_NNY (x4)
U_RST
ORHTU_H
EH_E_S
_I__ED
EH_RRY
SI__ED
EDDUSN_Y
U_STS
_I_URE
PEEWSIN_
YRRA_IN_
ITUAE____
R_MUEON

USEEON (x2)
DAHSOWY
SURHES

And I just stared at them and some words started to come out of the list:
DAHSOWY : Shadowy
EH_RRY  : Cherry
U_RST   : Burst
I_NNY   : Vinny
U_STS   : Busts
and then I noticed that the last 3 letters are always in the correct position, but the rest of the word is jumbled up:
DAHS : Shad
EH_  : Che
U_R  : Bur
I_  : Vi
U_  : Bu
And I noticed that these are just reversed again.
So I went back to the puzzle and for each of these long words I reversed all but the final three characters in the word.

AS THE _I_HT SHONE UPON _INNY, THE SY__EON REA_HED UP TO TOU_H HIM.
1Z 56B PHQ65 Z6L8B VRL8 UH88W, 56B ZWPUBL8 SB1G6B4 VR 5L 5LVG6 6HC.

JUST AS THE SY__EON TOU_HED _INNY, AN ESUEON _URST THROU_H THE DOOR, HIS _HEE_S _I__ED WITH _HERRY PIE.
TVZ5 1Z 56B ZWPUBL8 5LGV6B4 UH88W, 18 BZRBL8 7VSZ5 56SLVQ6 56B 4LLS, 6HZ G6BBAZ DHPPB4 EH56 G6BSSW RHB.

THE ESUEON WENT UP TO _INNY AND _ISSED HIM.
56B BZRBL8 EB85 VR 5L UH88W 184 AHZZB4 6HC.

SUDDEN_Y THE DOOR _USTS OPEN AND A SHADOWY _I_URE RUSHES IN SWEEPIN_ _INNY UP AND _ARRYIN_ THE _EAUTI___ UM_REON AWAY...
ZV44B8PW 56B 4LLS 7VZ5Z LRB8 184 1 Z614LEW DHQVSB SVZ6BZ H8 ZEBBRH8Q UH88W VR 184 G1SSWH8Q 56B 7B1V5HDVP VC7SBL8 1E1W...

Some of the words seems to have gotten muddled by my reversing techniques, but I can still fill in the words I figured out above. U=V, G=C, 7=B

AS THE _I_HT SHONE UPON VINNY, THE SY_VEON REA_HED UP TO TOU_H HIM.
1Z 56B PHQ65 Z6L8B VRL8 UH88W, 56B ZWPUBL8 SB1G6B4 VR 5L 5LVG6 6HC.

JUST AS THE SY_VEON TOU_HED VINNY, AN ESUEON _URST THROU_H THE DOOR, HIS _HEE_S _I__ED WITH _HERRY PIE.
TVZ5 1Z 56B ZWPUBL8 5LGV6B4 UH88W, 18 BZRBL8 7VSZ5 56SLVQ6 56B 4LLS, 6HZ G6BBAZ DHPPB4 EH56 G6BSSW RHB.

THE ESUEON WENT UP TO VINNY AND _ISSED HIM.
56B BZRBL8 EB85 VR 5L UH88W 184 AHZZB4 6HC.

SUDDEN_Y THE DOOR _USTS OPEN AND A SHADOWY _I_URE RUSHES IN SWEEPIN_ VINNY UP AND _ARRYIN_ THE BEAUTI___ UMBREON AWAY...
ZV44B8PW 56B 4LLS 7VZ5Z LRB8 184 1 Z614LEW DHQVSB SVZ6BZ H8 ZEBBRH8Q UH88W VR 184 G1SSWH8Q 56B 7B1V5HDVP VC7SBL8 1E1W...

Pat Sajak, I'd like to solve the puzzle.

As the light shone upon Vinny, the Sylveon reached up to touch him. Just as the Sylveon touched Vinny, an Espeon burst through the door, his cheeks filled with cherry pie. The Espeon went up to Vinny and kissed him. Suddenly the door busts open and a shadowy figure rushes in sweeping Vinny up and carrying the beautiful Umbreon away.